WASHINGTON -- The White House delivered a fresh warning to the Senate late Saturday to stay out of negotiations with Iran over its nuclear program, asserting that pending legislation would likely have a "profoundly negative impact" on the ongoing talks.
President Barack Obama's chief of staff, Denis McDonough, told Senate Foreign Relations Committee Chairman Bob Corker in a letter that legislation sponsored by the Tennessee Republican would go far beyond ensuring a role for Congress in any deal with Iran.
"Instead, the legislation would potentially prevent any deal from succeeding by suggesting that Congress must vote to 'approve' any deal," McDonough said. He criticized a provision that would eliminate Mr. Obama's authority to lift some sanctions on Iran as part of any agreement.
The talks are to resume Sunday in Switzerland, with the U.S. and other world powers facing an end-of-March deadline to reach a framework deal.
"The administration's request to Congress is simple: Let us complete the negotiations before the Congress acts on legislation," McDonough said, adding that he does expect a robust congressional debate if a final deal is struck by the end of June.
McDonough reiterated the president's repeated threats to veto the legislation should Congress pass it.
Corker and Senate colleagues in both parties insist that Congress be allowed to consider and vote on any agreement designed to block Iran from developing a nuclear weapon. Corker argued his case in a letter to Mr. Obama earlier this week, and did so again in response to McDonough.
"On this issue where Congress has played such a vital role, I believe it is very important that Congress appropriately weigh in before any final agreement is implemented," Corker said in a statement late Saturday.
Tensions between the administration and lawmakers over Iran have been rising for weeks.
McDonough's letter follows one this past week that was signed by 47 Republican senators and addressed to Iran's leaders warning that any nuclear agreement with the U.S. could expire the day Mr. Obama leaves office.
The White House blasted the letter as a politically motivated attempt to undermine the president's ability to conduct foreign policy and advance U.S. national security interests.
In an interview Saturday with CBS News, Secretary of State John Kerry told correspondent Margaret Brennan the letter "was absolutely calculated directly to interfere with these negotiations."
When asked if he planned to apologize for the Republican senators' action when he meets with Iranian Foreign Minister Mohammad Javad Zari on Sunday, Kerry responded, "Not on your life."
"I'm not going to apologize for an unconstitutional, un-thought-out action by somebody who's been in the United States Senate for 60-some days," Kerry said, referring to Sen. Tom Cotton, who spearheaded the letter. "That's just inappropriate."
Instead, Kerry said, "I will explain very clearly that Congress does not have the right to change an executive agreement."
The GOP letter follows a controversial March 3 speech to a joint meeting of Congress by Israeli Prime Minister Benjamin Netanyahu, in which he warned that the emerging nuclear agreement would all but guarantee that Iran gets nuclear weapons.
House Speaker John Boehner, R-Ohio, invited the prime minister to speak without input from the White House and State Department, in what the White House said was a departure from protocol.