Senators will continue debate over legislation that would allow Congress to weigh in on an Iran nuclear deal. 

Conservative Republicans have filed amendments that, if taken up, would force Democrats to the walk the line in a series of tough votes over Iran.
Senators are expected to convene at 3 p.m. Following leader remarks, they'll debate the Iran legislation for approximately two hours. 
At 5 p.m., they'll take up Dava Newman's nomination to be deputy administrator of NASA. A vote on the nomination is expected around 5:30 p.m. 
Meanwhile, the House will convene for a pro forma session at 8 p.m. No votes are expected.