When France withdrew in defeat in 1962, the guns quieted, but those tensions over identity only intensified in France.

Settlers, along with their supporters in France, experienced Algeria’s loss so profoundly that many still speak of reclaiming France’s lost glory — often while explaining their support for Marine Le Pen, the far-right presidential candidate.

Questions over French identity, opened by the war, still pit the French against one another.

The politics of nostalgia and grievance so closely parallel the American South, Mr. Stora said, that he has termed them “Sudisme à la Française.”

The parallel has its limits, but it highlights how disputes over the Algerian war’s legacy, while often too painful to confront directly, are reverberating in the French presidential election, which will end in a runoff on Sunday.