The United States Senate voted unanimously on Thursday in favor of a non-binding amendment to a budget bill intended to make it easier to re-impose sanctions if Iran violates a nuclear deal, Reuters reports. The vote was 100-0 for the amendment, sponsored by Republican Senator Mark Kirk, which would establish a fund to cover the cost of imposing sanctions if Tehran violated terms of an interim nuclear agreement now in effect, or the final agreement negotiators hope to reach before July. The votes are non-binding because the legislation will not become law, but many senators introduce amendments to send political messages, noted Reuters . Kirk, who is deeply skeptical of international negotiations on Iran's nuclear program, co-authored a bill that would tighten sanctions on Tehran, which President Barack Obama has threatened to veto as a threat to delicate international negotiations. Kirk and the bill’s co-author, Robert Menendez, toned down their sanctions bill in January, in an attempt to gain enough votes to override an Obama veto. The previous version of the bill and had been gaining momentum in Congress before Obama lobbied hard against it. Senate Majority Leader Mitch McConnell said on Tuesday the Senate would vote on Kirk's sanctions bill if international negotiators miss their deadline at the end of this month for reaching a framework nuclear agreement. If there is an agreement, he said, lawmakers would move ahead on a bill that would require Obama to submit the deal for Congress' approval. Obama has threatened to veto this bill as well. Republicans have demanded that any deal with Iran be brought for approval before Congress, while Obama has made clear that he will not submit any deal for approval. Republicans warned in a recent letter to Iran that doing so may mean that Congress or the next president will act to nullify the accord. The letter angered Obama , who suggested Republicans were “wanting to make common cause with the hard-liners in Iran.” Even Iran’s Supreme Leader, Ayatollah Ali Khamenei, criticized the letter and said it was a sign of the collapse of “political morality” in the United States.