In former President Donald J. Trump’s explanation of global events from the campaign trail, the world would not be aflame had he remained in the Oval Office.

Afghanistan? President Biden and Vice President Kamala Harris were responsible for setting off “the collapse of American credibility and respect all around the world.”

Iran, he insists, would not be arming Hezbollah, the Houthis or Hamas had he remained in office, or moving inexorably toward the capability to build a nuclear weapon.

“Israel would never have been invaded by Hamas,” he insisted in the debate that ultimately forced Mr. Biden out of the race. The war in Ukraine would never have happened, he added, “if we had a real president, a president who was respected by Putin.”

It is, of course, a politically appealing argument, if global crises unfolded in neat, four-year segments corresponding with the inauguration of presidents. The reality is that presidents inherit a world already hurtling through history.

In Mr. Biden’s case, that world was shaped, most immediately, by Mr. Trump himself — who struck the accord with the Taliban that governed the American withdrawal from Afghanistan, pulled out of the nuclear deal with Iran, did little to punish President Vladimir V. Putin of Russia for his takeover of Crimea and largely ignored the Palestinians during his years in office.