A key Iran bill under discussion on Capitol Hill is being toned down considerably amid criticism that its original version would doom the international nuclear agreement.

The legislation from Sen. Ben Cardin, D-Md., no longer conflicts with US commitments to lift sanctions on certain Iranian banks, according to a recent draft obtained by Al-Monitor. The latest version also removes an aggressive commitment to renew all sanctions on Iran and sweeps away an offer to provide Israel with bunker-busting super-bombs known as massive ordnance penetrators.

While the revised version is all but certain to leave Iran hawks wanting more, defenders of the deal still think it still goes too far. In particular, they argue that its explicit call for "expedited consideration" of terrorism-related sanctions appears to violate the letter and spirit of the Joint Comprehensive Plan of Action (JCPOA) signed July 14.

"The bill would no longer interfere with the president's implementation of the nuclear accord by requiring him to certify certain things in regards to Iranian banks," Tyler Cullis, a sanctions expert with the National Iranian American Council (NIAC), told Al-Monitor via e-mail when shown the new draft. "However, the bill has other problems — most especially, the fact that Congress is asserting unlimited authorities to impose sanctions on Iran for non-nuclear purposes and is instating an expedited procedure for legislation to do exactly such. In my reading, this is anathema to the JCPOA."