Chief of staff Denis McDonough tells Senate Foreign Relations Committee Chairman Bob Corker in a letter yesterday that legislation the Republican is sponsoring would potentially prevent any agreement from succeeding by asserting that Congress must vote to approve any deal.
McDonough also criticizes a provision that would undo President Barack Obama's authority to lift existing sanctions on Iran.
McDonough reiterates the White House position that congressional action before a deal is reached would be harmful to the talks, which are to resume Sunday in Switzerland.