As Congress returns from recess and prepares for important votes on President Obama's nuclear deal with Iran, many in Washington are already declaring the debate over. But the looming showdown over a resolution to disapprove the deal is no mere show vote.

It's true that through the raw exercise of power, Obama appears to have found a way to get his Iran deal around Congress despite bipartisan disapproval and opposition of the public. Even in the face of a presidential veto, however, there are still national security reasons for Congress to vote to reject the dangerous deal.

There have been three different layers of debate over the advisability of approving the Iran deal. The first has concerned the merits of the deal — whether it will or will not make the United States and its allies safer. The secondary argument has been about whether the deal, in spite of its flaws, was still the best of all alternatives. Then there's a tertiary argument over whether we're too far down this road to go back to the negotiating table, even if at some point in the past there may have been better alternatives. No matter the mode of analysis, the answer is clear: this is a rotten deal that deserves to be rejected.

For decades, the Iranian regime has distinguished itself as monstrously evil even by the standards of rogue states. It has oppressed its people, been a leading state sponsor of terrorism, held Americans hostages and killed Americans through its terrorist proxies. While in negotiations with the Obama administration and other world powers, Iran's theocratic leadership continued to embrace the slogan "Death to America," threaten to annihilate Israel and keep innocent Americans as prisoners.

Obama claims that he understands Iran is no great ally and that this is why he used diplomacy to prevent the nation from obtaining a nuclear weapon. In reality, Obama was so eager to strike a deal for the sake of his legacy that he not only provided a pathway for Iranians to obtain nuclear weapons, but ensured that should they choose to go nuclear, they will be doing so in a stronger position both economically and militarily, and more impervious to Western pressure.

The story of Obama's nuclear negotiations with Iran is a story of U.S. concessions, followed by more outrageous Iranian demands, followed by yet more U.S. concessions.

Back in 2012, the Obama administration was demanding from Iran "full suspension of uranium enrichment," which later got altered to a ceiling of 500 to 1,500 centrifuges. By the time the final agreement was signed, Obama and his allies were touting having limited Iran to 6,000 centrifuges.

Obama once said, "they don't need to have an underground, fortified facility like Fordow in order to have a peaceful nuclear program." But Fordow will remain open as a supposed scientific research facility, where the international community will be working with Iran to develop advanced centrifuge technology.

Despite claiming repeatedly during negotiations that Iran's ballistic missile program would have to be addressed, the deal lifts the U.N. embargo on conventional arms sales to Iran within five years and ballistic missiles within eight.

In the interim six months to a year, the deal will give Iran access to $100 billion to $150 billion in assets due to the unwinding of sanctions, providing the leading state sponsor of terrorism with more cash to finance attacks against the U.S. and its allies.

Obama, in defending the deal, has claimed, "this deal is not built on trust; it is built on verification." Rather than providing "anytime, anywhere" access, as once promised, Iran can object to inspections at undeclared nuclear sites, triggering a bureaucratic arbitration process that could be dragged out for over three weeks.

National Security Advisor Susan Rice declared in March, "Any deal must address the possible military dimensions of Iran's nuclear program."

But Iran's lead negotiator, Foreign Minister Mohammad Javad Zarif, told CNN in July, after the agreement had been signed, that "We've said very clearly that our military sites are off limits." In August, the Associated Press published text of a secret agreement between IAEA and Iran that the Obama administration refused to disclose to the public or members of Congress. Rather than provide inspectors with access to the Parchin military site, where it's suspected that nuclear detonation tests have been performed, Iran will provide photos, videos and seven "environmental samples" to inspectors.

Obama has declared: "If Iran cheats, the world will know." Setting aside the clear holes in the inspection regime that make this claim questionable, the obvious follow up is: if the world knows, what will the world do about it? Obama has made it clear through his actions that he doesn't view a military strike as a viable option, but he has promoted the idea that the deal would allow economic sanctions to "snap back" if Iran violates the deal.

But it isn't quite that simple. Re-imposing sanctions could only happen through a convoluted process requiring a 5 to 3 majority vote on a panel that includes China, Russia and Iran itself. So effectively, if the U.S. wanted to re-impose sanctions, the administration would have to get Britain, France, Germany and the EU on board.

Complicating matters is that if sanctions are re-imposed, Iran can void the entire deal and move ahead with its nuclear program. In fact, in a July 20 statement, Iran already put the U.N. on notice that it would "reconsider its commitments" under the deal if any sanctions are imposed — and this would apply not only to nuclear sanctions, but any other sanctions related to issues such as sponsorship of terrorism or human rights violations.

Defenders of the deal would argue even in the face of these criticisms that under the agreement, Iran would have less uranium, fewer operating centrifuges, and would be under greater supervision than without a deal. The agreement, the administration argues, extends the "breakout time" for Iran to get a nuclear weapon.

The problem is that even if one were to acknowledge that, we're left with a fatal flaw in the agreement — that it will begin to sunset in 10 to 15 years.

Obama has mused, "I've never understood the logic that says because there may be issues that we have to deal with 15 years from now, we should reject a deal that ensures us for 15 years not having a nuclear weaponized Iran."

Yet as a result of his deal, Iran will be undoubtedly in a stronger position in 15 years. It will transition from an economy that was on the brink of collapse due to crippling sanctions, to one that will have been freed of sanctions and thus much more robust. Once sanctions are lifted, European companies can start doing business in Iran, meaning that over time they'd build up more ties to the nation and they'd be lobbying their governments against any new sanctions. Due to the lifting of the arms embargoes, Iran will be able to obtain more sophisticated conventional weapons and ballistic missiles. And the U.S. and its allies would be working with Iran to protect its nuclear facilities against the threat of sabotage from traditional U.S. allies such as Israel.

Even in a best-case scenario in which the deal "works" Iran will have benefitted from decades of running an illicit nuclear program, by pocketing short-term economic and military gains, and still preserving its long-term ability to build nuclear bombs. This will provide an incentive for other bad actors to pursue a similar path, as well as encourage nations such as Saudi Arabia, Egypt, and Jordan to demand similar leniency.

"My fear is that, it's not that it's President Obama's deal or war," Mark Dubowitz, executive director of the Foundation for Defense of Democracies, told the Washington Examiner, referring to one of Obama's favorite talking points. "I think it's going to be Obama's deal and war. And when that war comes, Iran will be stronger and the consequences [of military action] are going to be much more severe."

Judged on its own merits, the deal is so problematic that even a number of Democratic members of Congress coming out in support of the deal have had to acknowledge its inherent weaknesses. For instance, Sen. Cory Booker, D-N.J., in announcing he would vote for the deal, called it "deeply flawed." He continued by saying, "We are in effect rewarding years of their deception, deceit, and wanton disregard for international law …"

The idea that there is no choice to this deal other than war is part of a broader effort to suggest opponents of the deal have offered no alternatives to this bad deal.

That isn't true. Critics have repeatedly offered a number of alternatives before, during, and after the negotiation process. Secretary of State John Kerry has dismissed these ideas as mere "fantasy." But what he now calls "fantasy" were once promises made by the administration as to what a final deal would look like (on uranium enrichment, military dimensions, inspections, missile technology and so on). Now Kerry argues that it was impossible that the U.S. could get a better deal out of Iran and that the sanctions would have unraveled had this deal not been signed.

But that's more of an acknowledgement of the impotence of Kerry and his negotiating team than it is a reflection of reality.

Iran's economy was in dire shape at the beginning of the negotiating process. The regime needed a deal a lot more than the U.S. There were several points at which the Obama administration could have walked away from the negotiating table and only returned had Iran agreed to American terms. Furthermore, to maintain pressure on Europe, the U.S. could have used secondary sanctions on European companies — forcing them to choose between doing business with faltering Iran, or with the world's largest economy.

It's hard to reconcile the administration's argument that, under the deal, it would be easy for the U.S. to get the Europeans to "snap back" sanctions (after the sanctions are lifted and European companies have had time to build ties to Iran) while saying it was completely inconceivable that the U.S. could have convinced other nations to keep the pressure on Iran until the regime agreed to a better deal.

That brings us to the third level argument, which is that even if we acknowledge it was a terrible deal and that Obama could have done a better job negotiating, we don't have a time machine. Now that the deal has been signed and was put through the U.N., aren't we stuck with it? Would walking away now bring international isolation? Would it be a gift to Iran's Supreme Leader Ali Khamenei, allowing him to walk away from the deal and blame the U.S.?

This line of thought isn't a good reason for accepting the terrible deal. If the U.S. were to say no, by the very logic of the deal's supporters, Iran would still have an incentive to abide by its part of the agreement to receive sanctions relief from the Europeans. But the U.S. would not be a party to the deal and thus could still pass its own stronger sanctions on Iran. By signing on, the U.S. has more flexibility to confront Iran as it wreaks havoc in the Middle East, sponsors terrorism and violates human rights – because the U.S. won't be hamstrung by fear that Iran will use any move as a pretext to void the deal.

Regardless of whether or not Obama will veto a resolution to disapprove the deal, congressional rejection of the deal would still be important.

It would be asserting the traditional separation of powers. Obama has set a terrible precedent — that a president can ignore the constitutional requirement to obtain two-thirds support for any treaty, go through the U.N. Security Council before the U.S. Congress and then present a major international agreement to Americans as a fait accompli.

Having a co-equal branch of government reject a deal that a majority of Americans oppose would send a clear signal to international firms seeking to do business in Iran that they better hold off, because U.S. policy toward the terrorist state could soon be dramatically different once Obama is out of office.

Make no mistake, the consequences of this deal are dangerous and potentially irreparable. But if there is any hope of reversing the damage, it will have to start with Congress overwhelmingly rejecting the deal and providing the next president a mandate to pursue a better course.

This article appears in the Sept. 8 edition of the Washington Examiner magazine.