March 19

IT’S EASY to conclude that Vladi­mir Putin’s passionate defense of Russia’s takeover of Crimea “just didn’t jibe with reality,” as Secretary of State John F. Kerry put it. In a speech on Tuesday, the Russian ruler repeated mendacious charges that the Ukrainian government had been hijacked by “nationalists, neo-Nazis, Russophobes and anti-Semites”; voiced his paranoid conspiracy theory about supposed Western sponsorship of popular revolutions, including the Arab Spring; and brazenly compared Russia’s abrupt annexation of Ukraine with the reunification of Germany.

It’s necessary, however, to take some of what Mr. Putin said seriously, because of the implicit threat it poses to European and global security. Mr. Putin advanced a radical and dangerous argument: that the collapse of the Soviet Union left “the Russian nation” as “one of the biggest, if not the biggest ethnic group in the world to be divided by borders.” That, he suggested, gave Moscow the right to intervene in Crimea, and, by extension, anywhere it considers ethnic Russians or their culture to be threatened.

Mr. Putin’s doctrine would justify Russian meddling not just in other parts of Ukraine — he claimed that “large sections of the historical south of Russia” now “form the southeast of Ukraine” — but also in other former Soviet republics with substantial populations of ethnic Russians.

Western officials seem to be betting that Mr. Putin won’t dare to extend his aggression beyond Crimea. But then, just last week they were saying they did not expect Moscow to move quickly on Crimean annexation. The Obama administration and its European allies have been too slow to grasp that Mr. Putin is bent on upending the post-Cold War order in Europe and reversing Russia’s loss of dominion over Eastern Europe, the Caucasus and Central Asia.

Worse, some in and outside of Western governments may be feeding Mr. Putin’s imperialism by rushing to concede “Russian interests” in Eurasia. President Obama and Mr. Kerry are among those who have said they recognize such “interests” in Ukraine. But the fact that there are ethnic Russians in a country should not give Mr. Putin’s regime a privileged say in its affairs. The idea that areas populated by Russians must be ruled or protected by Moscow is less the ideology of the 19th century, as Mr. Kerry would have it, than of the 1930s.

Mr. Putin’s claim that Russia should have a say in the political orientation of its neighbors, and whether they join alliances such as the European Union or NATO, is equally unacceptable. (Mr. Kerry recently renounced, gratuitously, any such U.S. claim on Latin American states, several of which have close military ties with Russia.) Perversely, some in the West are echoing Mr. Putin’s argument that his aggression is an understandable response to Western encouragement of the former Soviet Bloc states that embraced democracy and free markets and sought NATO and European Union membership.

The two countries that Mr. Putin has invaded since 2008, Ukraine and Georgia, were rejected for NATO membership action plans that year. Can it be argued seriously that Estonia and Latvia, with their large Russian minorities, now would be less vulnerable to Russian aggression had they had not joined NATO? The crisis in Europe has come about not because Western institutions expanded, but because they did not fulfill their post-Cold War promise of “a Europe whole and free.”