Oct. 15 will be decision day for President Donald Trump. That is the next deadline, under terms of the Corker-Cardin Iran Nuclear Agreement Review Act, for Trump to certify both that Iran is compliant with the Joint Comprehensive Plan of Action and that the Iran deal remains vital to the national security interests of the U.S.

Trump has pilloried the Iran nuclear deal he inherited as "the worst deal ever," but Defense Secretary James Mattis testified in Congress Tuesday that the JCPOA is working, and press reports suggest that Secretary of State Rex Tillerson wants to amend the Corker-Cardin legislation to relieve the pressure upon the president and to avoid battles about recertification every three months.

Not since Gen. Eric Shinseki so publicly contradicted President George W. Bush and Secretary of Defense Donald Rumsfeld has an administration's national security policy been so openly in disarray.

Disarray and debate, however, are the natural aftermath of the short cuts taken by the previous administration. Tillerson's solution misses the point. The problem isn't accountability to Congress; rather, it is that President Barack Obama and Secretary of State John Kerry sought to bypass the standard of crafting the JCPOA as a treaty.

True, had they done so, it would have been harder to reach agreement. But had they been shrewd enough to demand a standard necessary for Senate ratification as part of their negotiating strategy, they likely could have gotten a better deal. As it was, the deal is riven with loopholes and one which fell short of its original purpose.

As the deadline looms, supporters of the JCPOA say anything short of recertification will undermine credibility and isolate the U.S. It is naïve to suggest that there won't be diplomatic reverberations for Trump's refusal to certify, or that Iran will be willing to make further compromises. That said, unilateral sanctions are often more effective than those passed by the United Nations. That was the case with the Iran Libya Sanctions Act passed during the Clinton administration and the various executive orders Bill Clinton issued that embraced extraterritorial sanctions, and it was likewise the case with regard to the financial sanctions passed during the George W. Bush and Obama administrations. Simply put, Europeans always acquiesce to decisiveness and strength, be it from their allies or adversaries.

But when Iranian Foreign Minister Mohammad Javad Zarif, for his part, says, "You've seen U.S. allies saying that the United States is not a reliable partner," it's important to remember that it is the Iranian leadership broadly and Zarif specifically who have track records of lying. Remember the genesis of the nuclear crisis with Iran: The Islamic Republic was caught repeatedly violating its Nuclear Non-Proliferation Treaty Safeguards Agreement and then being less than forthright during follow-up inspections.

This is one of the reasons why the failure of the International Atomic Energy Agency to implement a clause which calls upon inspectors to verify "activities which could contribute to the design and development of a nuclear explosive device," is so problematic. To suggest that the agreement is working because the International Atomic Energy Agency has carried out no inspections which have found Iran cheating would be like arguing that the National Football League actually is steroids-free if the NFL allowed no tests to prove otherwise. Better to inspect the hell out of Iran, and if Tehran chooses to walk away, so be it.

Zarif's previous lies, meanwhile, cost hundreds of American lives. In the run-up to the 2003 Iraq War, Zalmay Khalilzad and Ryan Crocker — at the time respectively senior National Security Council and State Department officials — met then-UN Ambassador Zarif secretly in Geneva to win a non-interference agreement from Iran. Zarif acquiesced. He promised Iran would neither interfere with American pilots who strayed into Iranian airspace nor would Iran insert Islamic Revolutionary Guard Corps or Iranian-backed militias into Iraq.

Just days later, however, Iran infiltrated more than 2,000 Revolutionary Guardsmen and militiamen into Iraq. Perhaps Zarif was sincere but the IRGC acted autonomously. Either way, however, the failure of Zarif to keep his word raises questions whether he can be considered the arbiter of good faith.

Credibility matters, but the best way to assure credibility is to calibrate national security to reality rather than a carefully-crafted diplomatic fiction (no matter what the Nobel committee may say later this week when it awards the Nobel Peace Prize). Bad diplomatic agreements may win prizes, but they do not bring peace. Rather, they hasten conflict. When it comes to hard diplomacy with rogue regimes, there are never any short-cuts. Agreements are not treaties unless they are ratified as such. Nor can past agreements give permanent sanctions relief and an effective free pass to subsequent malfeasance.

Should Trump walk away from the deal? Probably not. But he should make its 90-day continuance contingent on implementation of all parts of the deal, no matter what objections the Kremlin may voice, and on the rapid inspection of Iranian military bases where nuclear weapons work might continue. Not only the deal is at stake, but the IAEA's relevance.

At the same time, he must prepare for the day that Iran either walks away from the deal, or the JCPOA sunsets. Because, far from eliminating Iran's pathway to a bomb, Obama and Kerry simply kicked the can down the road. Alas, the U.S. and Iran are heading far more quickly to its dead-end than diplomats blinded by projection, wishful thinking, and the temptation of trade realize.

Michael Rubin (@Mrubin1971) is a contributor to the Washington Examiner's Beltway Confidential blog. He is a resident scholar at the American Enterprise Institute and a former Pentagon official.

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