Last year, Marine Le Pen spoke menacingly of the possible fallout from her trial on embezzlement charges. “Tomorrow, potentially, millions and millions of French people will see themselves deprived of their candidate for the presidency.”

After a court disqualified her on Monday from running for public office for five years, those millions of French voters are adrift and angry. France is a democracy governed by the rule of law, as the verdict demonstrated. But it is unclear how far its troubled Fifth Republic can resist an inevitable gale of political protest before the 2027 election.

Unlike President Trump, who met with convictions, indictments and criminal cases on the way to his election last year, possibly even benefiting from perceived persecution, Ms. Le Pen could find no political path past the verdict of the French legal system.

“The independence of our justice system and the separation of powers stand at the heart of our democracy,” said Valérie Hayer, a centrist lawmaker in the European Parliament. “Nobody is above the law.”

That view is certain to come under sustained attack in a global environment where questioning of the legitimacy of legal systems has become frequent — across Europe, but particularly in Mr. Trump’s United States. Mr. Trump has called for the impeachment of judges who rule against him and called them “lunatics.”

“When the radical left can’t win via democratic vote, they abuse the legal system to jail their opponents,” Elon Musk, Mr. Trump’s billionaire aide, said after the verdict.

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