President Obama is certain to justify a less-than-perfect agreement with Iran by repeating his claim that the only alternative to a nuclear deal is war. Since this claim has resonance with the public and will be repeated endlessly by the news media, members of Congress should aggressively dispute it with three counterarguments.

First, war is obviously not an option for this administration, since there is no chance Obama would ever attack Iran. The Iranians know this.

Second, the status quo is infinitely better than the nuclear deal the Obama administration is seeking with Iran, since Obama’s bad deal will legitimize the nuclear program of a radical Islamist regime that is a sponsor of terrorism and committed to the destruction of the United States and Israel. This also is a regime that has developed its nuclear program in secret, engaged in nuclear-weapons-related research, and repeatedly violated obligations under the Nuclear Nonproliferation Treaty. Until there is regime change in Iran, the United States must work with its European allies to keep sanctions on Tehran that will deny it easy access to nuclear technology to slow its pursuit of nuclear weapons.

Third, a nuclear deal with Iran that allows it to continue to enrich uranium, develop advanced centrifuges, and keep a plutonium-producing reactor will be destabilizing and will undermine global nuclear-nonproliferation efforts. A deal that blesses Iran’s uranium-enrichment program will lead other states in the region and around the world to start their own uranium-enrichment programs. Legitimizing Iran’s nuclear program will embolden its adventurism in the region and increase the chances of an Israeli attack on Iranian nuclear facilities.

President Obama probably does not want to walk away from the nuclear talks because he does not want to be blamed for the failure and still wants a legacy agreement. It is my hope that the president’s legacy achievement with Iran will be walking away from a bad nuclear deal.

Failing this, Congress must hold the president to his word when he said that reaching no nuclear deal with Iran would be better than signing a bad deal. If an agreement is reached, we know it will be a bad deal, a deal that Congress must decisively reject.

Under the Corker-Cardin bill, passed in May, Congress can approve a resolution of disapproval that would prevent the president from lifting sanctions against Iran as agreed to in a nuclear deal. This would probably kill the deal. But as Andrew McCarthy has written, this is a deeply flawed process that turns the Constitution on its head, since agreements of this importance are supposed to be submitted as treaties and ratified by a two-thirds vote of the U.S. Senate. The president refuses to submit an Iran deal as a treaty, and the Corker-Cardin process requires a veto-proof majority to pass a resolution of disapproval, which means that only 34 senators are needed to defeat the resolution.

Getting a veto-proof majority to pass a resolution of disapproval will be a tall order. But the stakes here are very high, since the agreement Obama is seeking with Iran will do so much damage to international security and American interests. Even if the president vetoes a resolution of disapproval, a majority of Congress would have sent a signal to the world that there is strong opposition to the nuclear deal in the United States and, if a Republican is elected president in 2016, he or she is certain to reject this deal on his or her first day in office.