David A. Andelman, visiting scholar at the Center on National Security at Fordham Law School and director of its Red Lines Project, is a contributor to CNN and a columnist for USA Today. Author of "A Shattered Peace: Versailles 1919 and the Price We Pay Today," he was a foreign correspondent for The New York Times and CBS News in Asia and Europe. Follow him on Twitter @DavidAndelman. The views expressed in this commentary are his.

(CNN) President Donald Trump is about to come face-to-face with his next quarterly brush with Armageddon. Should he, or shouldn't he, scrap the Iran nuclear accord?

Any decision by him to "decertify" Iran's compliance, will have only a cataclysmic impact on the key issues he has cited for ending the pact and snapping back a range of tough sanctions that would accompany any such action.

The President would not be helping American or Western security. He certainly would not be helping hundreds of thousands of demonstrators who have taken to the streets across Iran.

What such a decision will do is seriously compromise American relations with all its major European allies, as foreign ministers of most European countries suggested on Thursday morning in a tense Brussels meeting.

At the same time, withdrawal would give new strength to Russia and China in global affairs -- united against the US in upholding what, to much of the world, appears to be the only real means of restraining Iran from developing nuclear arms. At the same time, America would be left even further isolated as a global pariah.