The motive behind the proposed repeal of the military’s “don’t ask, don’t tell” policy is, hmmm … what, exactly?

A stronger military? Better projection of American might in tight corners like Afghanistan and South Korea?

Well, not precisely any of that.

The whole idea of opening military enlistment to professed gays is the furtherance of the gay rights cause. It is what you might call an odd motive indeed for adoption of a military policy with mainly cultural implications.

That Congress has no clear idea how such a policy would work seems not to matter to its liberal promoters, clustered behind shoulder-boarded military brass who say with varying degrees of confidence and enthusiasm, yes, the thing can be done. Can be done isn’t—alas—the same thing as ought to be done: least of all in a time of war.

Defense Secretary Robert Gates, in Senate Armed Services Committee hearings, did not stunningly reassure Sen. John McCain, a third generation Naval man known to have acquired some insights into the ways of fighting men.

Gates was brandishing poll results purporting to show that 70 percent of military personnel thought that the insertion of gays into military units could likely work out. Oh? said McCain. What about the 58 percent of Marines and 48 percent of Army personnel otherwise minded?

“With time and adequate preparation,” said Gates, “we can mitigate their concerns.”

“Well, I couldn’t disagree more,” said McCain: pulling, if you like, moral rank.

Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, was no more persuasive than Gates. He noted that, yes, particular heterosexuals in the service might have a hard time with repeal of “don’t ask, don’t tell.” “Some may ask for different berthing,” he related. “Some may even quit the service.”

With what net gain for the military, and for the security Americans claim as an entitlement? As it happens, that’s the $64 trillion question: to which no bureaucrat or politician has an uncomplicated answer. For the sake of furthering an essentially political cause, Congress and the president are invited to throw open barrack gates to advocates for a political cause not guaranteed, shall we say, to perfect unity in battle.

Well, now, as everybody presumably knows, gays in the barracks wouldn’t be an innovation. The military has always had such—the difference between yesterday and today being, their presence in military units was inadvertent; when it was discovered, expulsion followed. Then gayness became a cause—a standard for rallying around. Whether the military needs explicit advocates for a cultural cause is the question McCain has tried to broach, with minimal cooperation from the military bureaucrats who work for President Obama.

Nobody—Gates, Mullen or McCain—knows explicitly how matters might work out should gays be incorporated freely and openly into the ranks. That is the point—nobody knows. Inferences nevertheless abound. What if McCain’s suspicions are correct, and sexual tensions—a potent enough factor with women now in the ranks—cause dissension, putting lives in danger? Are we willing to take that chance? If so, why?

Racial integration of the services following World War II was a different kettle of fish. For one thing, sex normally outranks race as a self-identifier. For another, black and white units already existed side by side; President Truman, in 1948, merely ordered their merger. A third difference: the country was at peace, and relatively unified, at the time of the merger.

Well, the liberal response is so what, in spirit if not words, to civilized objections such as McCain raises to taking chances with military security. This whole business after all isn’t about a stronger, better military. The drive to repeal “don’t ask, don’t tell” is about political promises to the gay rights movement and the urgency, as liberals see it, of keeping their base happy and voting liberal. Just what the country needs right now—political and cultural warfare over who fights our wars and on what terms.