When Donald Trump campaigned for a second term in the White House, he promised to be a “president of peace” who would stop foreign wars, not start them.

Now, a quarter-century after the 11 September, 2001, attacks that triggered America’s global “war on terror,” he is entangled in an unpopular conflict of his own making that analysts say risks becoming his version of a “forever war."

With the 9/11 anniversary at hand, Trump’s war against Iran is drawing comparisons in foreign policy circles to the long, divisive conflicts in Afghanistan and Iraq that preceded it. It is also prompting questions about whether the US has again failed to learn the lessons of past conflicts or prepare a clear exit strategy.

“Trump has broken an important post-Iraq and Afghanistan constraint in Washington against launching another major, open-ended war in the Middle East,” said Sina Toossi of the Center for International Policy, a Washington think tank. “That could leave his successor inheriting ... an entrenched US-Iran confrontation.”