Jen Psaki, blameless State Department spokeswoman, explained that the hasty evacuation of our embassy in Yemen was not an evacuation but “a reduction in staff.” This proved a problem because the Yemeni government had already announced (and denounced) the “evacuation” — the word normal folks use for the panicky ordering of people onto planes headed out of the country.

Thus continues the administration’s penchant for wordplay, the bending of language to fit a political need. In Janet Napolitano’s famous formulation, terror attacks are now “man-caused disasters.” And the “global war on terror” is no more. It’s now an “overseas contingency operation.”

Nidal Hasan proudly tells a military court that he, a soldier of Allah, killed 13 American soldiers in the name of jihad. But the massacre remains officially classified as an act not of terrorism but of “workplace violence.”

The U.S. ambassador to Libya and three others are killed in an al-Qaeda-affiliated terror attack — and for days it is waved off as nothing more than a spontaneous demonstration gone bad. After all, famously declared Hillary Clinton, what difference does it make?

Well, it makes a difference, first, because truth is a virtue. Second, because if you keep lying to the American people, they may seriously question whether anything you say — for example, about the benign nature of NSA surveillance — is not another self-serving lie.

And third, because leading a country through yet another long twilight struggle requires not just honesty but clarity. This is a president who to this day cannot bring himself to identify the enemy as radical Islam. Just Tuesday night, explaining the U.S. embassy closures across the Muslim world, he cited the threat from “violent extremism.”

The word “extremism” is meaningless. People don’t devote themselves to being extreme. Extremism has no content. The extreme of what? In this war, an extreme devotion to the supremacy of a radically fundamentalist vision of Islam and to its murderous quest for dominion over all others.

But for President Obama, the word “Islamist” may not be uttered. Language must be devised to disguise the unpleasantness.

Result? The world’s first lexicological war. Parry and thrust with linguistic tricks, deliberate misnomers and ever more transparent euphemisms. Next: armor-piercing onomatopoeias and amphibious synecdoches.

This would all be comical and merely peculiar if it didn’t reflect a larger, more troubling reality: The confusion of language is a direct result of a confusion of policy — which is served by constant obfuscation.

Obama doesn’t like this terror war. He particularly dislikes its unfortunate religious coloration, which is why “Islamist” is banished from his lexicon. But soothing words, soothing speeches in various Muslim capitals, soothing policies — “open hand,” “mutual respect” — have yielded nothing. The war remains. Indeed, under his watch, it has spread. And as commander in chief he must defend the nation.

He must. But he desperately wants to end the whole struggle. This is no secret wish. In a major address to the National Defense University just three months ago he declared “this war, like all wars, must end.” The plaintive cry of a man hoping that saying so makes it so.

The result is visible ambivalence that leads to vacillating policy reeking of incoherence. Obama defends the vast NSA data dragnet because of the terrible continuing threat of terrorism. Yet at the same time, he calls for not just amending but actually repealing the legal basis for the entire war on terror, the 2001 Authorization for Use of Military Force.

Well, which is it? If the tide of war is receding, why the giant NSA snooping programs? If al-Qaeda is on the run, as he incessantly assured the nation throughout 2012, why is America cowering in 19 closed-down embassies and consulates? Why was Boston put on an unprecedented full lockdown after the marathon bombings? And from Somalia to Afghanistan, why are we raining death by drone on “violent extremists” — every target, amazingly, a jihadist? What a coincidence.

This incoherence of policy and purpose is why an evacuation from Yemen must be passed off as “a reduction in staff.” Why the Benghazi terror attack must be blamed on some hapless Egyptian-American videographer. Why the Fort Hood shooting is nothing but some loony Army doctor gone postal.

In the end, this isn’t about language. It’s about leadership. The wordplay is merely cover for uncertain policy embedded in confusion and ambivalence about the whole enterprise.

This is not leading from behind. This is not leading at all.

• Charles Krauthammer writes for the Washington Post.