Even just the sowing of doubt about the future of the agreement has economic effects—by stoking wariness in the private sector about doing any new business with Iran—that make the JCPOA less attractive to Tehran.  This week’s White House statement, bristling with threats to pull out of the agreement, serves that purpose for Trump.

The overall effect of all of the administration’s hostile measures, including formal ones as well as wariness-stoking rhetorical ones, is similar to what the administration has done to another major accomplishment of Trump’s predecessor, the Affordable Care Act.  That process already has gone far enough for Trump to claim last month, “We essentially repealed Obamacare.”  He cannot yet make that claim about the JCPOA, but that’s the direction he’s headed.

It will be a tragedy that a measure that serves the interests of the United States and of international security and the cause of nuclear nonproliferation will fall victim to a campaign of destruction driven by motives as base as the ones Trump exhibits.  It will be no less a tragedy for happening gradually rather than all at once.