Sen. Angus King (I-Maine) says he still supports legislation that would let Congress weigh in on a final nuclear deal with Iran but only if his colleagues treat the measure “responsibly.”

King, one of the bill’s original co-sponsors, said he had spoken with Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) and warned him that “if this looks like this is just going to be used as a partisan issue, some way to embarrass the president, to deny him of foreign policy achievement, I'm out, man.”

The deal “is one of the most important agreements of our lifetimes. And I think we're close. I want to see the details, I want to let them negotiate further, see what it actually looks like when it's finalized in June,” he added during an interview on MSNBC’s “Andrea Mitchell Reports.”

King’s comments come the day before Corker’s panel is set to take up the measure, which would require President Obama to wait 60 days before lifting any economic sanctions against Iran. The pause is meant to give Congress time to review a final accord, and could lead to additional votes to approve or nix the deal.

The administration has repeatedly warned the bill could scuttle the talks, which are set to continue through the end of June.