Protesters in Ukraine. Photo: Wikipedia.

Rarely have the consequences of President Obama’s disinterest in American national security been so evident as in Ukraine’s ongoing crisis.

After essentially ignoring Ukraine for five years, Obama now faces armed hostilities in a large Central European country, with important U.S. interests at stake and no idea what to do. In fact, it may be too late for us to prevent tragedy.

It didn’t have to be this way.

Obama has begged both President Victor Yanukovich’s authoritarian government and the opposition protesters to exercise restraint and resolve their differences peacefully. The Europeans have only imitated Obama’s posturing, proposing embarrassingly weak economic sanctions.

Candidate Obama indulged in a similar flight of fancy in August 2008, when Russia invaded Georgia, another former Soviet republic. Obama then also urged both sides to exercise restraint — a weak, feckless response doubtless carefully noted in the Kremlin.

Today, Obama shares a position with Ron Paul, who says that America has no interest in Ukraine’s internal dispute and should stay out. Obama argues essentially the same thing: “I don’t think this is a competition between the United States and Russia,” he said Wednesday, adding “our approach … is not to see this as some Cold War chessboard.”

By contrast, Russia’s foreign ministry takes a hard line, comparing Ukraine’s protesters to the 1930’s “brown revolution” that brought Nazis to power in Germany.

Paul and Obama are flatly wrong, displaying a contemporary version of pre-World War II isolationism.

The West made a major mistake in 2008 when Europeans rejected Washington’s proposal to put both Georgia and Ukraine on a clear path to NATO membership, settling instead for vague, aspirational statements. Four months later, Russian troops entered Georgia, and Russia increased its efforts to subvert Ukraine’s struggling young democracy.

Today, we may be on the verge of seeing Russia’s strategy pay off, and the West’s exposed as hollow.

America should assert unambiguously that it will urgently press for full NATO membership for a democratic Ukraine. This is precious little, but it is the only way to give hope to Ukrainians who want to prevent being pulled back into Moscow’s orbit.

John Bolton is a former U.S. ambassador to the UN under President George W. Bush.

This article was originally published by the New York Daily News.