President Trump’s attempt to blow up the Iranian nuclear deal isn’t foreign policy. It’s vandalism.

Trump is abandoning the Iran deal, with nothing to replace it, even though his own secretary of state and chairman of the Joint Chiefs of Staff say that Iran appears to be in compliance; even though his own secretary of defense says that staying in the deal is in America’s interest; even though our allies are pleading to stick with it. The reason for Trump’s decision seems obvious: The deal was President Barack Obama’s.

This petty retreat from diplomacy is the most significant national security move Trump has made. It means that Trump is isolating the United States, not Iran, and it increases the risk of military conflict down the road. If there’s anything we should have learned, it’s to avoid unnecessary wars in the Middle East — but Trump may be laying the groundwork for yet another.

“Many regard the invasion of Iraq as the worst foreign policy move in the history of the American republic,” James Dobbins, a much respected retired diplomat, tweeted after Trump’s speech. “Now we have a competitor.”

The Iranian deal may not permanently solve the problem of Iran’s pursuit of nuclear weapons, but it delays any crisis for nearly 15 years or more. Trump doesn’t want to risk a possible crisis then, so he chooses to have one now — apparently, just for the satisfaction of kicking sand at Obama.