Senate Democratic leaders put out a narrow Iran sanctions bill July 14, just hours after Sens. Bob Corker (R-Tenn.), Bob Menendez (D-N.J.) and others filed a measure to expand sanctions against Iran and restrict when the administration could waive them. Sen. Ben Cardin (D-Md.), pictured, is among those backing the Democrat-sponsored bill. (Andrew Harnik/AP)

Senate Democratic leaders filed legislation late Thursday to extend current sanctions against Iran with no major changes, a sign that the party is not interested in helping the GOP secure more bipartisan support for a bill directing broader and stricter sanctions against Tehran.

The bill proposed by Senate Minority Leader Harry Reid (D-Nev.) and backed by Senate Foreign Relations Committee Ranking Member Ben Cardin (D-Md.), Sen. Charles E. Schumer (D-N.Y.), and 11 others, is a simple reauthorization of the Iran Sanctions Act, or ISA, which outlines trade, energy, defense and banking sector sanctions over Iran’s nuclear and missile activities.

The current ISA expires at the end of the year, and many lawmakers argue it is vital to renew it in order to keep a credible threat of “snap-back” sanctions alive, should Iran overtly break its obligations under its nuclear deal with the United States and other countries.

The proposal was filed just hours after Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) filed a bill co-sponsored by Sen. Bob Menendez (D-N.J.), Marco Rubio (R-Fla.) and Joe Manchin (D-W.Va.) to renew the ISA along with new mandatory sanctions against people and entities involved with Iran’s ballistic missile program, the Iranian Revolutionary Guard Corps, and cyber-threats and espionage activities.

That bill would also prohibit the president from waiving such sanctions in order to implement any future agreements with Iran without congressional approval.

Though that proposal’s two Democratic supporters both voted against the Iran deal, Corker hoped that over time, he could build up more bipartisan support for the proposal, potentially enough to vote on it in September.

But Cardin and Schumer were the other two senators to vote against the Iran deal last year — and adding their names to the no-frills reauthorization of the ISA so soon after Corker’s bill was introduced is a sign Democrats won’t be joining Republicans in their effort to pass an Iran bill with stiffer waiver limitations than usual.

As recently as early spring, Cardin had been exploring with Corker a way to impose more-expansive sanctions on Iran, particularly over its ballistic missile activities. But their efforts began to move in different directions about three or four months ago, at which point Corker teamed up with Menendez to work on the bill they unveiled Thursday.

Some are also urging the White House to push for more transparency regarding how Iran is or is not complying with the nuclear agreement. On Friday, 15 Democratic senators led by Gary Peters of Michigan sent President Obama a letter urging the administration “to ensure that the IAEA releases all relevant technical information” about its compliance inspections, “so that we may continue to make our own judgments about the status of Iran’s nuclear program.”

They requested more information about the amount of low enriched uranium in Iran and the current centrifuge count, among other technical details.

“We supported the JCPOA,” the senators wrote, adding it was still “the best available option” to keep Tehran from getting a nuclear weapon. “We are committed to ensuring that the terms of the agreement are enforced.”

In prior legislation, Cardin also proposed measures to strengthen the Iran deal. But earlier this week, he said those suggestions had been an “area of contention” with Republican lawmakers.

That is one of the things that led Cardin to conclude that a straight, unadulterated reauthorization of the ISA was the best hope of getting something through Congress this year.

Administration officials “are not necessarily promoting any particular legislative strategy at this point,” Cardin told reporters Wednesday. “They’ll be very pleased if Congress does nothing.”

Menendez, independently, suggested it wouldn’t be such a bad thing if Congress simply passed a reauthorization of the ISA, and returned to work on a more comprehensive package of Iran sanctions after the election.

“There’s a lame duck session, where the politics don’t have to be a part of it,” Menendez said. Another alternative, he said, would be for lawmakers to simply use the next few months “to build a foundation” for next year.

Corker, however, did not want to commit to a backup plan if his measure failed to gain enough support to pass the Senate.

If the parties largely retreat to their camps over this, it will be difficult to get a bill through the Congress before the end of the year.

Senate Majority Leader Mitch McConnell (R-Ky.) has already said that he would not bring up a bill that didn’t have at least 67 votes — that being the number of senators necessary to overcome a presidential veto.

And there is even less likelihood that senators will be able to build bipartisan compromise around Iran-related measures the House passed this week. Those bills would step up sanctions against Iran over its ballistic missile program, human rights violations and support for terrorism, prevent Tehran from engaging in offshore dollarized transactions and block the administration from striking any more deals to purchase heavy water from Iran. Each vote split the House nearly along the party line.