ROME — This month, Matteo Salvini, the surging leader of Italy’s anti-migrant League party, announced that he’d had it with his own coalition government and wanted new elections.

“I ask the Italian people if they want to give me full powers to do what we have promised to do, and go all the way without hurdles,” the perennially campaigning Mr. Salvini said at a rally on Aug. 8.

But he seems to have underestimated one rather large hurdle — an Italian parliamentary system that makes America’s Electoral College look elementary and the angling around Brexit seem the stuff of babes.

On Tuesday, a no-confidence vote sought by Mr. Salvini is scheduled against Prime Minister Giuseppe Conte. That would seem to signal the end of Mr. Salvini’s rocky coalition with the anti-establishment Five Star Movement, seal the fate of the 65th Italian government since the end of World War II and open the door to new elections.