Rep. Berman: Don't 'give in' to White House efforts to soften Iran sanctions plan

"If the administration is to be strong, the Congress must be stronger," Berman said at a Foundation for the Defense of Democracies-sponsored forum, according to the Washington Times.

"I will not — and Congress should not — give in to entreaties from the administration or elsewhere on the particular issue we're now faced with to dilute our approach to sanctions on the Central Bank of Iran's petroleum transactions," Berman said.

Berman and many other lawmakers from both sides of the aisle are ready to tighten the screws on the Central Bank of Iran, aiming to convince — by squeezing their finances — the regime in Tehran to give up its nuclear arms program.

An international nuclear watchdog says Iran is closer than ever to fielding a nuclear weapon. Lawmakers want the Obama administration to get more aggressive in its efforts to stop Iran; the White House is standing by its sanctions-based approach, while leaving a military strike on the table.

At issue is what to do about an amendment to the Senate's 2012 Pentagon policy bill that would sanction firms and governments that do business with the Central Bank of Iran. The Senate approved that measure in a rare 100-0 vote. Pressuring the Iranian central bank is seen as one of the few remaining forceful sanctions options, and whether to use military force to take down Iranian nuclear sites will be a big 2012 presidential election issue.

Sen. Mark KirkMark KirkThe Hill's 12:30 Report Trump, judges on collision course GOP senator: Don't link Planned Parenthood to ObamaCare repeal MORE (R-Ill.) said this week the unanimous vote "sent a message" to the administration, adding its political support on Iran among lawmakers "has collapsed."

The Senate aide told DEFCON Hill House and Senate conferees are working with the administration on a compromise version of the plan that Kirk crafted with Sen. Robert MenendezRobert MenendezSteve Mnuchin, foreclosure king, now runs your US Treasury Senate Dems move to nix Trump's deportation order Senators to Trump: We support additional Iran sanctions MORE (D-N.J.).

"Ranking member Berman is going to be the key holdout," the aide said.