The 60-day congressional review period has expired, and the State Department last week outlined its plan to put in place an accord that aims to prevent Iran from acquiring nuclear weapons.
Still, Congress is poised this week to work on legislation to reinstate sanctions or shore up what some lawmakers say is an ill-fated pact.
One proposal being discussed calls for stepping up oversight of Iran's compliance.
Another measure would reauthorize existing penalties under the Iran Sanctions Act, which expires at the end of 2016. Other legislation would bolster security for Israel and U.S. allies in the Persian Gulf. Opponents worry the deal will increase Iran's influence in the region.