The chairman of the Senate Foreign Relations Committee warned President Barack Obama on Thursday not to try an end-run around Congress by getting the United Nations to implement a nuclear deal with Iran.

Republican Sen. Bob Corker of Tennessee cited reports that the Obama administration was contemplating taking an agreement to curb Iran’s nuclear program — or at least parts of it — to the U.N. Security Council for a vote.

In a letter, Corker said letting the U.N. consider such an agreement, while at the same time threatening to veto legislation that would allow Congress to vote on it, is a “direct affront” to the American people and would undermine the role of Congress. In exchange for signing onto a deal aimed at keeping it from developing nuclear weapons, Iran seeks relief from sanctions, including those imposed by the U.S. executive branch, the United Nations and Congress.

Corker has introduced legislation requiring any final agreement with Iran to be submitted to Congress for review before any sanctions imposed by Congress can be eased.

On Tuesday, State Department spokeswoman Jen Psaki raised the possibility of establishing the deal through the U.N. Security Council. Psaki didn’t speak definitively on the matter but cited the example of a 2013 strategy agreed to between the U.S. and Russia on Syria relinquishing its chemical weapons stockpile. That plan was then endorsed by the United Nations’ top body.

“This framework was not legally binding and was not subject to congressional approval,” Psaki told reporters. “It outlined steps for eliminating Syria’s chemical weapons and helped lay the groundwork for successful multilateral efforts to move forward.” In that case, she added, the U.S.-Russian agreement “went to the U.N. to the Security Council vote.”

Iranian Foreign Minister Mohammad Javad Zarif is the only official who has gone on record saying such a model would be followed with a nuclear deal.

U.S. negotiators have been more circumspect. Making such a declaration would amount to telling Congress that it won’t have a say on the accord, because it is not a treaty, but that the United Nations will.

(AP)