Jewish Democrats on Capitol Hill are at the center of a fierce tug of war over the Iran deal.

On one side are lobbyists for the American-Israel Public Affairs Committee and Israeli diplomats, who have been active in an effort to kill the deal’s chances.

And on the other is the Obama administration, as Cabinet secretaries tour the Hill to sell it.

With Republican leaders firmly against the nuclear agreement, the fate of the deal will likely come down to how Democratic lawmakers choose to vote. And though some Jewish Democratic lawmakers — like California Sens. Dianne Feinstein and Barbara Boxer — have indicated their inclination to support the agreement, many more have stayed mum.

But on Tuesday, Secretary of State John Kerry leaped on an opening from Rep. Sander Levin (D-Mich.), the longest-serving Jewish member of Congress, during a hearing before the House Foreign Affairs Committee.

Levin announced his support for the deal just a few hours earlier, saying in a statement: “I believe that Israel, the region, and the world are far more secure if Iran does not move toward possession of a nuclear weapon. I believe the Agreement is the best way to achieve that.”

Kerry insisted on reading that section of Levin’s statement to the lawmakers present in the Foreign Affairs committee room, though they assured him they were already aware of it and probably didn’t need to hear it again.

Yet Kerry’s zeal to reiterate Levin’s words were part of a greater push to prove his sensitivity to Israel and his pro-Israel bona fides. He seemed to want to convince lawmakers being pressured by pro-Israel lobbyists that there is nothing anti-Israel in supporting the deal.

Levin’s early backing of the Iran deal lays down a marker for other Jewish members of Congress and Democratic representatives of heavily Jewish House districts, who are struggling under competing pressures from pro-Israel lobbyists and the head of their party in the White House. To be sure, there are dozens of other lawmakers who have also voiced serious concerns about Israel’s security.

But only a handful of them — such as Democratic National Committee chairwoman and Rep. Debbie Wasserman Schultz (D-Fla.) or Sen. Charles E. Schumer (D-N.Y.), neither of whom have announced how they will vote — would arguably speak with more personal authority about Israel’s interests.

It was clear at Tuesday’s hearing that many Democratic lawmakers still had serious concerns about how well the deal would protect Israel.

“I would like to know how, specifically, will we work with our allies to minimize the potential windfall to terrorist organizations, and protect our allies like Israel,” said Rep. Eliot Engel (D-N.Y.), the ranking member on the House Foreign Affairs Committee. “Our friends in Israel rightfully are concerned that Iranian funding of terrorism would continue to affect them in an existential way.”

Democratic Reps. Brad Sherman (D-Calif.) and Ted Deutch (D-Fla.) also raised concerns about Iran’s ability to continue or even increase funding for militant groups wreaking havoc in the Middle East and posing a serious threat to Israel and the United States.

“They’re holding four American hostages. Assad is killing 5,000 people a month and the blood is on the hands of men in Tehran,” Sherman said. “They’re supporting Hamas, Hezbollah and the Houthi, and those are just the organizations that begin with the letter H.”

Kerry tried to establish his credibility on Israel by citing his voting record on pertinent matters as a senator.

“In the 28 years, a little more, that I was privileged to represent Massachusetts, I had a 100 percent voting record on every issue for Israel,” Kerry told the committee in his opening Tuesday. “I understand the fear, I understand the concerns that our friends in Israel have. But we believe that what we have laid out here is a way of making Israel and the region, in fact, safer.”

He was backed up by Energy Secretary Ernest Moniz, who often gets a kinder reception than Kerry from lawmakers.

“I’m confident this is a good deal for America, for our allies and for our global security,” Moniz said, quoting a letter from several former U.S. ambassadors to Israel, reiterating: “This landmark agreement removes the threat that a nuclear armed Iran would pose to the regions and to Israel specifically.”

That, of course, is not the line that Israel’s leaders, chief among them Prime Minister Benjamin Netanyahu, have taken on the deal. Netanyahu remains vehemently opposed to it, and has argued it only gives Iran a more legitimate pathway to making a bomb and will embolden terrorists in the region.

Some lawmakers tried to create openings Tuesday for Kerry to argue why Netanyahu’s take was wrong.

“You concluded, Mr. Secretary, that this agreement makes the world, our allies, including Israel, and the region safe,” said Rep. David Cicilline (D-R.I.), inviting Kerry to “just provide for us kind of some thinking of why it is that the current Israeli leadership does not see it that way.”

But the chorus of anti-deal voices remains far louder.

“We fully understand every Israeli has concerns, has fears. There are concerns about the region they live in, about the nature, the rhetoric that’s used. Death to Israel, death to America — everybody is concerned,” Kerry said “But I will tell you, there are people in Israel who…”

“You’re going to name a couple of people,” interrupted an exasperated-sounding Rep. Steve Chabot (R-Ohio), who asked Kerry how he could defend the Iran deal over Netanyahu’s opposition. “The prime minister is against it. And I’m almost out of time.”