Hours before Iran struck an American military base in Qatar on Monday in retaliation for the bombing of three of its nuclear facilities, U.S. President Donald Trump said what some experts feared could lead to history repeating itself.

In a post on his social medial platform Truth Social on Sunday afternoon, Trump wrote, “Why wouldn’t there be a regime change???”

For Mohamad Tavakoli-Targhi, a professor of Near and Middle Eastern civilizations at the University of Toronto, the answer is existential.

If the U.S. were to overthrow Iran’s government — again — Tavakoli-Targhi said, “it’s going to create a bigger chaos in the Middle East than one could ever imagine.”