SINCE THE election of President Trump, the biggest question in Western politics has been whether a version of his populist insurgency, and the similar anti-establishment fever that prompted Britain’s vote to leave the European Union, will spread to the Netherlands, France and Germany in elections scheduled for the coming months. If it does, the European Union could be buckled by further withdrawals and the West as an identifiable collective based on liberal values could crumble — something that some in Mr. Trump’s administration, if not the president himself, would apparently welcome.

The chances for such an outcome look real: Polls show the leading candidates in the Netherlands and France have included Geert Wilders and Marine Le Pen, both of whom share Mr. Trump’s anti- immigrant and anti-Muslim agenda, along with antipathy toward the European Union and, in the case of Ms. Le Pen, admiration for Russia’s Vladi­mir Putin. In Germany, the Alternative for Germany party peddles a similar agenda, though its chances to enter government are slight.

Yet in both France and Germany, recent weeks have seen a refreshing surge by candidates who are perceived as outsiders, yet are committed to mainstream policies and institutions. In Germany, Social Democratic Party candidate Martin Schulz, a former president of the European Parliament, has suddenly appeared to challenge Chancellor Angela Merkel; dubbed a “politically correct populist,” Mr. Schulz has made no secret of his disregard for Mr. Trump and has adopted the slogan “Make Europe Great Again.”

Even more significantly, Ms. Le Pen’s chances of sweeping to victory may have been checked by the rise of Emmanuel Macron, a charismatic 39-year-old former banker who describes himself as a radical centrist and who this week took over first place in a poll . Mr. Macron, who founded his own party called En Marche, or “Forward,” has assaulted the certainties of the French political establishment, such as its reliance on statist ecomomic policies, and championed social liberalism, including religious freedom. As The Post’s James McAuley reported, he infuriated the traditional left by attacking the 35-hour workweek even as he angered the traditional right by calling France’s colonization of Algeria a “crime against humanity.”

Not surprisingly, Mr. Macron’s sensible if unconventional liberalism has made him a target for Russia’s state propaganda apparatus, which having done its best to tip the U.S. election to Mr. Trump is now attempting to empower Ms. Le Pen. According to Mr. Macron’s campaign manager, Moscow’s Internet cadres have conducted “hundreds and even thousands” of hacking attacks against the party, and outlets such as RT and Sputnik are spewing fake news about the candidate, such as claims that he is secretly gay.

It would be foolish to suppose that this campaign, and the demagogic appeals of Ms. LePen, cannot succeed. For now, however, it is looking as if the reaction in Europe to Mr. Trump’s victory may be the consolidation of forces that oppose his radical assertion of national sovereignty over multilateralism, and economic nationalism over free trade. If so, that will be a victory for all who still believe in a liberal democratic West.