Once again, President Trump is engaging in cynical behavior on the Iran nuclear deal, refusing either to retreat from his ill-informed campaign posturing about the agreement or to follow through on his vow to dismantle it. Instead, he’s trying to position others as the fall guy for a future US withdrawal from the multiparty pact.

In October, Trump refused to certify that Iran was complying with the deal, but stopped short of applying sanctions for that supposed noncompliance. Instead, he left that up to Congress to decide. Congress did nothing, and wisely so: In November, the International Atomic Energy Agency, which monitors the accord, said that Iran was in fact in compliance.

Because of reporting requirements, the certification cycle recurs every 90 days. Thus on Jan. 12, the president again declined to certify that Iran was in compliance, but again declined to reimpose sanctions. Instead, Trump threatened that if the other parties to the pact — Great Britain, Russia, France, Germany, and China — and Congress don’t strengthen it within 120 days, he will withdraw the United States from the deal. Among other things, Trump wants to change the inspections regime, remove the expiration dates on the agreement’s provisions, and include restrictions on Iran’s missile program.

Those conditions read like a calculated effort to undermine the pact. The original thinking behind the agreement was that Iran’s alleged nuclear aspirations should be addressed as its own discrete issue. Other concerns would be dealt with separately, since including them would add multiple layers of geopolitical complexity.

The United States obviously can’t impose Trump’s new demands unilaterally. And there’s absolutely no reason to believe the other parties to the pact will embrace them; they think, correctly, that the agreement is working. Russiahas already ruled that out, and France, Britain, and Germany have made it clear they back the current deal. Thus there’s no way a new arrangement could be presented as a unified-front ultimatum to Iran by world powers. And even if all parties, including Iran, were willing to reopen the agreement, it’s absurd to expect a renegotiation of this scope and complexity could be completed in 120 days. So Trump is obviously not looking for a solution, but rather attempting to position others as the scapegoat should he pull out of the arrangement at some future point, as he is threatening to do.

In that light, it’s important to underscore several important truths Trump has long ignored. By requiring the alteration of Iran’s heavy-water reactor, the deal has closed the path to a plutonium bomb. By dramatically reducing Iran’s stockpile of enriched uranium, it has lengthened from a couple of months to at least a year the time it would take Iran to enrich enough uranium for a bomb. And as far as detection goes, the agreement gives the International Atomic Energy Agency 25 years of inspections of Iran’s nuclear-materials cycle.

Finally, if Trump does withdraw the United States from the pact and reimpose sanctions, absent the other countries following suit, that solo action would be unlikely to force Iran to accept new terms. All Trump would really have done is undermine an antinuclear-proliferation effort that has been a significant success so far. In other words, the president is currently engaged in a cynic’s errand.

It’s past time for the president to change course. No, the Iran deal isn’t perfect. Rather, it was an exercise in the art of the possible. But it has made the Middle East safer — and sticking with it is preferable to any realistic alternative.