Congress hasn't managed to pass a single Iran-related bill since the nuclear deal went into effect last year, but that doesn't mean its supporters can breathe easy. 

Behind the scenes, lawmakers in both chambers and both parties have been working together on comprehensive legislation that will seek to punish Iran for its human-rights abuses, ballistic missile tests and other activities. That strategy could help explain why a bill to renew sanctions on Iran's energy sector that expires at the end of the year has been bottled up in the Senate banking panel for the past 11 months despite bipartisan support for its passage.

"My sense on the Republican side is that the leadership is not going to accept a mere extension [of the Iran Sanctions Act] without additional sanctions," said Sen. Robert Menendez, D-N.J. "Certainly I want to get it done, period. But if it helps drive a bigger package, that's a good thing."

Menendez, a member of the Senate Foreign Relations Committee who opposed the Iran deal, has been working for months with panel chairman Bob Corker, R-Tenn., on broader sanctions legislation. That effort is on the verge of succeeding, Corker told Al-Monitor May 11.