Here's what's in the Iran nuclear deal, and what happens next. (Gillian Brockell and Julio C. Negron/The Washington Post)

After two months of uncertainty, President Obama is going to get his Iran nuclear deal through Congress -- potentially with ease.

As of Tuesday, it's clear that Obama and his fellow Democrats will prevent the Republican-controlled Congress from passing and upholding a resolution of disapproval that would derail the historic nuclear deal that the United States and five other nations reached with Iran in July.

Even better for the president: Senate Democrats could possibly block a vote to derail the Iran deal from even coming up. There are now 42 senators on record supporting the deal, which would be enough to prevent Senate Republicans from officially voting on a resolution of disapproval.

But that's only if at least 41 vote to effectively filibuster the resolution. Some senators, such as Sen. Chris Coons (D-Del.), have suggested they'd prefer an up-or-down vote on the deal instead of blocking it altogether.

But the ability to filibuster an Iran resolution would be icing on the cake for the president. In August, Obama secured 34 senators to uphold his veto if Congress passed the resolution of disapproval.

Even getting to magic No. 34 was a major diplomatic and political victory for Obama. Recent polls have shown the Iran deal is unpopular with most American voters as the debate has become more partisan, making the decision to support the deal even more excruciating for some Senate Democrats. Congress was the last piece of the international puzzle to allow the deal to go forward.

As you'll see below, any vote on the Iran deal will come down mostly along party lines. Only four Democrats -- Sens. Ben Cardin (Md.), Joe Manchin (W.Va.), Charles E. Schumer (N.Y.) and Robert Menendez (N.J.) -- have said they will not support the deal.

Below is the whip count. We've been monitoring all the senators' comments on the issue and classifying them accordingly. And if we miss anything or classify a senator wrongly, make sure to let us know via e-mail.

Current state of play

(Updated 6:44 p.m. Sept. 8)

Yes (34 needed to keep the deal): 42

No or leaning no (67 needed to override veto, kill the deal): 58

Unknown/unclear: 0

And now, the 100 senators ...

Yes (42)
  • Sen. Tammy Baldwin (D-Wis.): “I’m proud that America led six countries toward an historic international agreement with Iran."
  • Sen. Michael Bennet (D-Colo.): "This agreement represents a flawed, but important step to accomplish those goals."
  • Sen. Richard Blumenthal (D-Conn.): "While this is not the agreement I would have accepted at the negotiating table, it is better than no deal at all. And it can be made even better through unilateral American action and collaboration with our European allies," he said in a Sept. 8 statement.
  • Sen Cory Booker (D-N.J.): "We have now passed a point of no return that we should have never reached, leaving our nation to choose between two imperfect, dangerous and uncertain options. Left with these two choices, I nonetheless believe it is better to support a deeply flawed deal, for the alternative is worse," he said in a Sept. 3 statement.
  • Sen. Barbara Boxer (D-Calif.): "If this agreement is what the Administration says it is, it is a major, historic diplomatic breakthrough.”
  • Sen. Sherrod Brown (D-Ohio): “This deal is not about trusting the Iranian regime, but instead working with our allies on comprehensive, verifiable restrictions to block Iran's pathways to a nuclear bomb without precipitating another war in the Middle East" he said Aug. 14.
  • Sen. Maria Cantwell (D-Wash.): "Because the agreement calls for the reduction of highly enriched uranium stockpiles, bringing centrifuges offline and converting key nuclear infrastructure to civilian use, including its nuclear reactors, it moves Iran’s breakout time from two months to one year," she said in a Sept. 8 statement.
  • Sen. Tom Carper (D-Del.): "This is a good deal for America, our negotiating partners and the world. That’s not just my view. It’s also the view of scores of American national security leaders and former senior officials, as well as many of their Israeli counterparts," he wrote in an op-ed Aug. 28.
  • Sen. Bob Casey (D-Pa.) "I firmly believe that effective implementation of the [agreement], bolstered by other U.S. policies, including a strong deterrence policy of the U.S. and our partners, will be in our national security interest," he wrote in a 17-page statement released Sept. 1.
  • Sen. Chris Coons (D-Del.): "We are better off trying diplomacy first," the previously undecided senator told The Washington Post before giving a speech announcing his support for the deal.
  • Sen. Joe Donnelly (D-Ind.): "Despite having questions about Iran’s intentions, I am willing to give this agreement the opportunity to succeed," he said in an Aug. 19 statement.
  • Sen. Dick Durbin (D-Ill.): "The United States, working with our allies, has reached a historic agreement with Iran that, according to President Obama and Secretary Kerry, will prevent Iran from obtaining a nuclear weapon. I commend our negotiators for this critical effort. Finding a diplomatic solution will make our country, our allies, and the world a safer place."
  • Sen. Dianne Feinstein (D-Calif.): "I stand behind the U.S. negotiating team and will support this agreement in the Senate."
  • Sen. Al Franken (D-Minn.):"This agreement is, in my opinion, the most effective, realistic way to prevent Iran from getting a nuclear weapon anytime in the next 15 years. It does so by imposing a series of physical limits on Iran's nuclear program, especially its production of the fissile material it would require to make a bomb," he wrote in a CNN op-ed Aug. 13.
  • Sen. Kirsten Gillibrand (D-N.Y.) wrote on Medium Aug. 6 "Why I'm supporting an imperfect Iran deal", saying "Iran made essential concessions in the deal" and " this deal will provide international nuclear inspectors with access that they otherwise would not have had ."
  • Sen. Martin Heinrich (D-N.M.): "[T]he numbers under this deal look a hell of a lot better than what we got under the previous policy," Heinrich told Politico.
  • Sen. Heidi Heitkamp (D-N.D.): " This agreement dramatically reduces the chances Iran ever acquires a nuclear weapon by taking concrete, verifiable steps to constrain Iran’s possible uranium enrichment and plutonium reprocessing activities," she wrote in a piece published on Medium on Sept. 3.
  • Sen. Mazie Hirono (D-Hawaii): "While this agreement is not perfect, it has gained broad national and international support, including 29 top American nuclear scientists, of which six are Nobel laureates," she said Aug. 18.
  • Sen. Tim Kaine (D-Va.): " I think if it matches the April 2 framework and there is a solid verification and inspection regime, I think it’s going to be good for our national security," he said on PBS July 15th.
  • Sen. Angus King (I-Maine): "A nuclear-armed Iran would be a serious threat to the United States and to the world, but this agreement, if implemented effectively, would prevent Iran from obtaining the capacity to build a nuclear weapon for at least another fifteen years," he said Aug. 19. 
  • Sen. Amy Klobuchar (D-Minn.): In a statement Aug. 10, she said the deal is imperfect but it offers the "best available option to put the brakes on Iran's development of a nuclear weapon," according to the AP.
  • Sen. Patrick Leahy (D-Vt.): "We thought we were negotiating in good faith and we'd have a deal. If we walk out now, many of these countries are going to say, 'okay, you're in it by yourself,'" he said Aug. 5.
  • Sen. Ed Markey (D-Mass.): "This agreement is far from perfect and carries risks. But I believe our negotiators achieved as much as they reasonably could, and that if strictly implemented, this plan can be effective," he said Aug. 19.
  • Sen. Jeff Merkley (D-Ore.): "[M]any have argued that the United States, instead of implementing the agreement, should withdraw from it, persuade our partners to set the agreement aside and work together to negotiate a better deal,” Merkley said in a statement Aug. 30. “However, the prospects for this are slim. All of our partners ... believe that the current deal — in regard to its central goal of blocking Iran’s pathways to a nuclear bomb — is sound. They have committed the good faith of their governments behind the agreement and intend to honor the deal as long as Iran does likewise, with or without the United States."
  • Sen. Claire McCaskill (D-Mo.): The moderate Democrat was originally undecided and on Aug. 20 said "This deal isn't perfect and no one trusts Iran, but it has become clear to me that the world is united behind this agreement with the exception of the government of Israel."
  • Sen. Barbara Mikulski (D-Md.): "I've asked if we reject this deal, what the alternatives are that would be effective and achievable. I’ve considered the alternatives very closely. But in the end, they don’t present a more viable option to this deal. The two alternatives are more sanctions, or military action," she said in a statement Sept. 2.
  • Sen. Chris Murphy (D-Conn.): "I've said for some time that the best way to stop Iran from obtaining a nuclear weapon is through diplomacy, not war. And after very thoughtful consideration over the past several weeks, I believe that more than ever," he said in an Aug. 5 press release.
  • Sen. Patty Murray (D-Wash.): One of the Democratic Party's leaders came out in support of the deal Aug. 25, saying in a statement: "I am convinced that moving forward with this deal is the best chance we have at a strong diplomatic solution, it puts us in a stronger position no matter what Iran chooses to do, and it keeps all of our options on the table if Iran doesn't hold up their end of the bargain."
  • Sen. Bill Nelson (D-Fla.): "Unless there is an unexpected change, I will support the nuclear agreement," he said Aug. 4.
  • Sen. Gary Peters (D-Mich.): Peters was an original co-sponsor of the 2015 Kirk-Menendez Iran sanctions bill that Obama said would put unnecessary pressure on the negotiations. In a statement Sept. 8, he said: "Despite my serious reservations, I will reluctantly vote against a motion of disapproval because I believe that doing so will protect the credibility of the United States to hold Iran accountable to adhere to every single obligation in the [deal]. But if Iran fails to meet its international obligations under this accord, I will support the immediate reinstatement of Congressional sanctions, and I will encourage my colleagues in Congress to do the same."
  • Sen. Jack Reed (D-R.I.): "If Iran cheats, they will be isolated, international sanctions snap back, and we will have better intelligence, a broader coalition, and a stronger case for swift, forceful action," said the ranking member of the Armed Services Committee on Aug. 18.
  • Senate Minority Leader Harry Reid (D-Nev.): "I’m going to do everything in my power to make sure the deal stands," he told The Washington Post on Aug. 23, saying was "cautiously optimistic" he'd be able to prevent an override of Obama's veto of a resolution disapproving the deal.
  • Sen. Bernie Sanders (I-Vt.): "So I think we go as far as we possibly can in trying to give peace a chance, if you like. Trying to see if this agreement will work. And I will support it," he told CBS's Face the Nation Aug. 7.
  • Sen. Brian Schatz (D-Hawaii): "Despite the partisan rancor in Washington, the vast majority of experts believe this is a worthy deal," he said in an Aug. 10 statement.
  • Sen. Jeanne Shaheen (D-N.H.): "I've concluded this is the best available option we have for preventing Iran from obtaining a nuclear weapon," she said in an Aug. 6 statement.
  • Sen. Debbie Stabenow (D-Mich.): "I have determined that the imminent threat of Iran having a nuclear weapon outweighs any flaws I see in the international agreement," she said in an Aug. 24 statement.
  • Sen. Jon Tester (D-Mont.)
  • Sen. Tom Udall (D-N.M.): "This is a historic moment. This agreement has profound impact if we approve it and -- make no mistake -- if we fail to approve it," he said in a July 30 speech.
  • Sen. Mark Warner (D-Va.): "While I believe there are several areas of concern with the agreement, the choice I ultimately had to make was between accepting an imperfect deal, or facing the serious ramifications if Congress rejected a deal that has the support of the rest of the world," he said in a Sept. 3 statement.
  • Sen. Elizabeth Warren (D-Mass.): "The question now before Congress — the only question before Congress — is whether the recently announced nuclear agreement represents our best available option for preventing Iran from acquiring a nuclear weapon,” she said in a statement to The Boston Globe. “I am convinced that it does.”
  • Sen. Sheldon Whitehouse (D-R.I.): "Short of war, with all its dramatic uncertainties and terrible costs, I do not see another pathway to impose a nuclear weapons-free Iran," he said Aug. 18.
  • Sen. Ron Wyden (D-Ore.): "No one can be certain what will happen if this agreement is rejected, but all signs point to even more risk and even less stability in the region," he wrote in a post shared on Medium on Sept. 8. "Our international partners, who helped negotiate this agreement and who now stand behind it, have only reinforced that point, both in public and in my private conversations. If this agreement is rejected the most likely scenario is not one in which a chastened Iran returns to the negotiating table hat in hand to make additional concessions, but rather one where Iran’s leaders continue to test and install new centrifuges and edge ever closer to the bomb, free from the intrusive inspections that this agreement would create."
Leaning no (10)
  • Sen. John Barrasso (R-Wyo.)
  • Sen. Shelley Moore Capito (R-W.Va.)
  • Sen. Thad Cochran (R-Miss.): "Iran cannot be allowed to gain nuclear weapons capabilities, and I am skeptical whether the agreement reached by the Obama administration is truly verifiable and enforceable."
  • Sen. Mike Crapo (R-Idaho): "The consequences of a bad deal are monumental," he said in May.
  • Sen. Mike Enzi (R-Wyo.): He signed a Republican human rights letter to Secretary of State John Kerry saying "we are concerned the Obama Administration is failing to recognize the inherent danger of engaging in nuclear negotiations with this particular regime given their appalling record on human rights."
  • Sen. Orrin Hatch (R-Utah)
  • Sen. Dean Heller (R-Nev.)
  • Sen. Mike Lee (R-Utah)
  • Sen. Pat Roberts (R-Kan.)
  • Sen. Mike Rounds (R-S.D.): "It is important that any deal is enforceable so that we can keep Iran accountable," he said in May.
No (48)
  • Sen. Lamar Alexander (R-Tenn.): "“The agreement puts some limits on Iran’s nuclear program, but it also legitimatizes it, thereby encouraging a nuclear arms race in the most unstable area of the world," he said Aug. 31.
  • Sen. Kelly Ayotte (R-N.H.): The deal is a "historic capitulation" she told Fox News on July 14.
  • Sen. Roy Blunt (R-Mo.)
  • Sen. John Boozman (R-Ark.): "We have a responsibility to ensure that Iran never achieves its goal of becoming a nuclear power. This deal give us little confidence that we will be successful in this regard."
  • Sen. Richard Burr (R-N.C.): " The President’s plan inadequately addresses Iran’s technological nuclear advancement, which would need better monitoring than this plan provides. We owe the American people, the Israeli people, and our allies in the region our best possible effort to rein in a known state sponsor of terrorism," he said in an Aug. 5 statement.
  • Sen. Ben Cardin (D-Md.): "This is a close call, but after a lengthy review, I will vote to disapprove the deal," he said in a Sept. 4 Washington Post op-ed.
  • Sen. Bill Cassidy (R-La.): "I'm looking at it from an American perspective. Relaxing the sanctions gives Iran the resources and ability to buy (long-range) missiles or secure technology to build them," he told the Shreveport Times on Aug. 12.
  • Sen. Dan Coats (R-Ind.): "Rather than negotiate from a position of strength, the P5 + 1 negotiators’ desire for a deal led them to negotiate from a position of weakness. The result is an agreement with benefits too small, a duration too short and a cost too high," he said in a column  July 30.
  • Sen. Susan Collins (R-Maine): "[Iran] already has the deeply troubling capability to launch missile strikes at Israel, which it has pledged to wipe off the face of the earth. ICBM technology poses a direct threat to our nation from a nation whose leaders continue to chant 'Death to America!,'" she said on the Senate floor on Sept. 8. 
  • Sen. Bob Corker (R-Tenn.): "Rather than end Iran’s nuclear enrichment program, over time this deal industrializes the program of the world’s leading state sponsor of terrorism," The chair of the Senate Foreign Relations Committee wrote Aug. 17 in a Washington Post op-ed.
  • Sen. John Cornyn (R-Tex.): "This deal just gets worse and worse the more you dig into it," he told Fox News on July 24.
  • Sen. Tom Cotton (R-Ark.): "If this deal is approved, it will represent a historic defeat for the United States."
  • Sen. Ted Cruz (R-Tex.): "If this deal is consummated, it will make the Obama administration the world’s leading financier of radical Islamic terrorism," he said July 29.
  • Sen. Steve Daines (R-Mont.): "If Iran’s ultimate goal is to obtain a nuclear weapon, the deal reached by the Obama administration sets Iran on a course to do so," he wrote in an Aug. 18 op-ed.
  • Sen. Joni Ernst (R-Iowa): "I see this as a pathway to nuclear armament, not getting rid of it. These people are not our allies, they are not going to change overnight," she told CNN on July 30.
  • Sen. Deb Fischer (R-Neb.): "I believe we send a message, not just to the world, but we send a message to our allies, we send a message to Iran: This isn’t a good deal. And the administration has the support of Congress to work for a better deal," she told the Omaha World-Herald Aug. 21.
  • Sen. Jeff Flake (R-Ariz.): The Senate Foreign Relations Committee member said Aug. 15 the deal's benefits "are outweighed by severe limitations the (agreement) places on Congress and future administrations in responding to Iran's non-nuclear behavior in the region,
  • Sen. Cory Gardner (R-Colo.): "This deal is unwise. For the sake of the region, and the sake of the world, it must be rejected."
  • Sen. Lindsey Graham (R-S.C.)
  • Sen. Chuck Grassley (R-Iowa): "We gave practically everything away,” the Iowa Republican said Thursday. “Why were we negotiating in the first place?," he told the Omaha World-Herald Aug. 21. 
  • Sen. John Hoeven (R-N.D.): "We have a choice—and it isn't between this deal and war. The choice is between keeping in place sanctions that are working or a deal that paves the path to a nuclear Iran. I choose strong sanctions and a safer America," he wrote in an Aug. 23 op-ed in Grand Forks Herald.
  • Sen. Jim Inhofe (R-Okla.)
  • Sen. Johnny Isakson (R-Ga.): "I will not be part of any agreement that allows the Iranians to develop a nuclear weapon," he said in a statement Aug. 19.
  • Sen. Ron Johnson (R-Wis.): "I just think this is a really bad deal. [President Obama] is just doing this on his own, and there’s not much we can do about it," he said Aug. 26, according to the Jackson County Chronicle.
  • Sen. Mark Kirk (R-Ill.): "This agreement will enrich and empower Iran, the world’s foremost sponsor of terrorism."
  • Sen. James Lankford (R-Okla.): "This Congress should not process things under fear, and this Congress should not process things saying you’re the last in line so you better sign up to where the rest of the world is," he told the Edmond Sun on Aug. 11.
  • Sen. Joe Manchin (D-W.V.): “For me, this deal had to be about more than preventing Iran from acquiring a nuclear weapon for the next 10-15 years. For me, this deal had to address Iran’s terrorist actions. Without doing so would reward Iran’s 36 years of deplorable behavior and do nothing to prevent its destructive activities," he said in a Sept. 8 statement published in The Exponent Telegram.
  • Sen. John McCain (R-Ariz.): "We’re losing and we’re losing badly," he told The Daily Signal on July 15.
  • Senate Majority Leader Mitch McConnell (R-Ky.): ""I think it's a terrible deal for America. I'm going to vigorously oppose it, and I believe all members of my party are as well," he told local WBKO radio on Aug. 25.
  • Sen. Bob Menendez (D-N.J.): Menendez co-authored a bill that would have put sanctions on Iran if negotiations failed by June 30 and was the second prominent Democrat to come out against the deal. "If Iran is to acquire a nuclear bomb, it will not have my name on it," he said.
  • Sen. Jerry Moran  (R-Kan.): "I’m convinced more than ever the nuclear agreement negotiated by the Obama administration is damaging to our country’s national security and it increases the risk to our allies and friends in the Middle East," he said in a statement July 18.
  • Sen. Lisa Murkowski (R-Alaska): “In light of the progress that Iran has made in its quest to develop a nuclear weapon, it is imperative to me that an agreement not simply arrest Iran’s nuclear ambitions but require the abandonment of those ambitions. The agreement before us, viewed in the most favorable light, does not accomplish this goal," she said Aug. 21.
  • Sen. Rand Paul (R-Ky.)
  • Sen. David Perdue (R-Ga.): "This deal won’t protect Iran from becoming a nuclear weapons state—it just delays it."
  • Sen. Rob Portman (R-Ohio): "falls far short of our own stated goals and that of the international community. This is another example of another red line the administration has drawn but failed to honor.”
  • Sen. Jim Risch (R-Idaho): "This deal falls disastrously short of what the Obama Administration originally promised and gives the Iranian government what it desires."
  • Sen. Marco Rubio (R-Fla.): "I expect that a significant majority in Congress will share my skepticism of this agreement and vote it down."
  • Sen. Ben Sasse (R-Neb.): "The Administration just lit the fuse for a nuclear arms race in the Middle East."
  • Sen. Tim Scott (R-S.C.): "This deal will fund more bad behavior in the Middle East. I don't want to be a co-conspirator on that deal," he told Greenville County Republican Women on Aug. 20.
  • Sen. Jeff Sessions (R-Ala.)
  • Sen. Chuck Schumer (D-N.Y.): The likely next-in-line Democratic leader and ally of Israel said Aug. 6 he cannot support the Iran deal. "In the first ten years of the deal, there are serious weaknesses in the agreement," he wrote on Medium. His "no" vote is a big loss for Obama and deal supporters.
  • Sen. Richard Shelby (R-Ala.): "“If Putin’s for it, why would we be for it," he said July 16.
  • Sen. Dan Sullivan (R-Alaska)
  • Sen. John Thune (R-S.D.): "A nuclear armed Iran is a threat to the United States, and an agreement that allows Iran to retain all the components necessary to build a nuclear bomb is not a good deal for America and should be rejected," he wrote in a July 24 op-ed. 
  • Sen. Thom Tillis (R-N.C.)
  • Sen. Pat Toomey (R-Pa.) "The Iran deal enables a terrorist machine," he wrote in an Aug. 3 op-ed.
  • Sen. David Vitter (R-La.): "This agreement is a really, really bad deal for America, for Israel, and for freedom."
  • Sen. Roger Wicker (R-Miss.): "When you’re dealing with somebody, you consider the past conduct of who you’re negotiating with … the people in charge of Iran have shown no indication that they’re trustworthy," he told WAPT News Jackson on Aug. 18.