To understand why Iran will cheat on the nuclear deal, you have to look back to September 2013: the month following Bashar al-Assadโ€™s chemical-weapons attack on Ghouta, Syria, and the moment Assad challenged Americaโ€™s red line over weapons of mass destruction โ€” the moment America blinked. America would forgo military action, President Obama said at the time, if Assad gave up his WMDs. Sensing Americaโ€™s trepidation, Assad surrendered some WMDs and gave Mr. Obama his pretense. But he kept other WMDs. With them, Assad is continuing to kill his people. This absurdity helps explain why Americaโ€™s credibility in the Middle East has collapsed. But the credibility deficit isnโ€™t just about Assad. Today, years after President Obama warned President Putin about aggression, Putin is openly mocking America, The Russian leader is modernizing S-300 anti-aircraft missile systems for Iran and challenging the investigation into the downing of MH-17. Eastern Ukraine remains defined by war.

Iranโ€™s conclusion: Rhetoric is cheap, and cheating America comes without negative consequences. Correspondingly, Iran will wait until it has established a ballistic-missile capability before constructing an actual nuclear weapon. Iranโ€™s leaders are careful strategists โ€” patient and determined. In the early months of this deal, they know that the international community will carefully judge Iranโ€™s compliance. To build a semblance of trust, they are therefore likely to cooperate with inspectors. But a year from now, when the prospect of a sanctions snap-back is gone thanks to EU business interests and Russian trade deals, Iran will start cheating. At that point, Iranโ€™s leaders will use states like North Korea to attain a ballistic-missile-nuclear-warhead capability. And forget sanctions. On Tuesday, John Kerry affirmed that Iranian cheating on ballistic-missile weaponization would not lead to a sanctions snap-back. Iran knows that it can build a nuclear delivery platform without meaningful consequences.

Iran knows that it can build a nuclear delivery platform without meaningful consequences.

Still, the Obama administration veils its weakness under the masquerade of enlightened diplomacy. Without humanitarian action to sustain it, Mr. Obamaโ€™s foreign policy is defined by moral humility. Iranโ€™s leaders โ€” Rouhani included โ€” play to this delusion. They present the Islamic Republic as the guardian of justice and democratic virtue. This imagined reality sits perfectly with many American liberals who believe that Iranโ€“U.S. tensions are ultimately the product of emotion. They believe that Iran funds such groups as the Lebanese Hezbollah because of the 1953 Mosaddegh affair (in which the CIA overthrew Iranโ€™s prime minister) and 1980s feuding. And they believe Mr. Obamaโ€™s nuclear deal will spark the trust to overcome these differences.

#related#Unfortunately, this is delusion. The real roots of Iranโ€“U.S. discord run much deeper. Iran wants to establish an arc of hyper-sectarian Khomeinism across the Middle East. Thatโ€™s why Iran wants a nuclear weapon and thatโ€™s why Ayatollah Khamenei (or his successor) will cheat at the first moment it becomes possible and logical. As the Senate considers President Obamaโ€™s deal, it should bear this consideration in mind. It should also remember that there are real alternatives short of war. A naval blockade, as proposed by General James Mattis, would tighten the noose around the Revolutionary Guards and force Khamenei into a simple choice: negotiate, or accept a Praying Mantis redux, and the destruction of Iranโ€™s naval forces.

โ€“ Tom Rogan is a writer and a panelist on The McLaughlin Group. His homepage is http://www.tomroganthinks.com.