Brinksmanship: Assimilate the worst features of populism in order to defeat it.
Finally, you could determine that the stakes are existential and dig in for a ferocious battle. If you believe that populism and nationalism will, if unimpeded, vitiate your democracy, destroy your freedom to express your views, fill your society with an irrational fear of foreigners, and make your country an authoritarian nightmare, you could . . . opt to do all those nasty things on behalf of liberalism. Don’t like the democratic verdict? Ignore it. Or delegitimize it as the product of nefarious Russian interference. Think the populists are leveraging digital platforms to advance their agenda? Make legal-sounding threats until Silicon Valley transforms itself into the de facto speech police and ministry of propaganda for the liberal order. Encourage your most unstable people in utter hysteria and accept that a few of them may try to shoot congressman or assault people in the streets on behalf of the liberal world order. Make memes celebrating them.