Of course, just because some of these doomsday scenarios haven’t yet materialized doesn’t mean that they won’t eventually. A number of Trump’s actions have already inflicted serious damage and could have corrosive consequences that will only become evident over time. In some cases, Trump seems to have simply been lucky. A number of warnings, moreover, have proved right.

Nevertheless, as American foreign policy comes under greater scrutiny as part of this year’s presidential campaign, the Democratic candidates risk losing credibility with voters and undermining their policy prescriptions if they don’t reckon with the moments when they said the sky was falling and it wasn’t. Why should a voter be convinced that returning to aspects of the pre-Trump status quo is necessarily a good thing when the people advocating for that inaccurately diagnosed the results of Trump’s defiance of convention? The episodes in which critics’ predictions weren't borne out offer valuable lessons for Trump’s challengers, even if they still vigorously disagree with the moves the president has made.

Read: The Sanders doctrine

As Charles Dunlap Jr., the head of Duke University’s Center on Law, Ethics, and National Security, wrote for Just Security early in the Trump administration, Americans “need balance in our national security and foreign policy discussions before we don sackcloth and ashes and hoist our ‘The End is Near’ signs. True, we are in an era of change, which is what happens in democracies when a candidate runs on a platform of change and wins, and change can be disquieting to those who prefer the status quo. But how good was the status quo?”

Consider three emblematic episodes:

The War With Iran That Wasn’t

In the wee hours of January 2, shortly after news broke that Trump had killed the Iranian commander Qassem Soleimani in a drone strike, Twitter pulsed with anxiety about #WWIII.

Enter the Democratic candidates: Bernie Sanders warned that Trump had just placed the United States “on the path to another” endless war, one that could again “cost countless lives and trillions more dollars.” Joe Biden declared that Trump had “just tossed a stick of dynamite into a tinderbox,” potentially bringing America to “the brink of a major conflict across the Middle East.” The U.S. was perched precariously on that brink, Elizabeth Warren argued, “because a reckless president, his allies, and his administration have spent years pushing us here.”

Read: Qassem Soleimani haunted the Arab world

The calamitous war they envisioned, however, has not come to pass. They were right, though, that there would be devastating consequences. Iran retaliated by firing missiles at a U.S. base in Iraq, leaving at least 109 American troops with traumatic brain injuries. The Iranians mistakenly downed a civilian airliner, killing its 176 passengers, and hostilities between Iran and the U.S. remain dangerously high. Tehran has cast off restrictions under the 2015 deal brokered by the Obama administration to constrain Iran’s nuclear program, though it hasn’t yet raced to build a bomb, as many of Trump’s critics predicted would happen when the president withdrew from the agreement in 2018. Had Trump stuck with the accord in the first place, Iran and the U.S. might never have found themselves on the precipice of war over Soleimani’s demise.