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.
Senate Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellSenate passes 6B defense bill Poll: Kim Jong Un has higher approval among Republicans than Pelosi The Hill's Morning Report — Sponsored by PhRMA — Outcry raises pressure on GOP for immigration fix MORE (R-Ky.) last week pledged that the Iran bill would get a “robust amendment process.”
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.