It’s genocide — now what?

At the eleventh hour, just after informing Congress that the government would miss a legal deadline, Secretary of State John Kerry Thursday announced that, yes, the ongoing brutal bloodletting of thousands of Christians, Yazidis and Shiite Muslims by the murderers of ISIS is in fact a genocide.

The declaration is momentous. Only once before, in 2004, has the U.S. blown the whistle on a genocide-in-progress — that time in the Sudan, but only after State Department lawyers assured then-Secretary of State Colin Powell that it wouldn’t obligate the U.S. to intervene.

So absorb today’s cognitive dissonance: The U.S. prosecutes a war against ISIS in Syria and Iraq and even now Libya, through the air and with special forces boots on the ground. But the command- er-in-chief remains intent on preventing deeper involvement — even as his administration declares a crime of historic proportions is underway.

The same Obama administration has a top foreign policy staffer, UN Ambassador Samantha Power, who wrote “A Problem from Hell,” a book about America’s obligation to protect would-be victims from just such mass murder. In it, she wrote:

“[T]his country’s consistent policy of nonintervention in the face of genocide offers sad testimony not to a broken political system but to one that is ruthlessly effective.

“No U.S. President has ever made genocide prevention a priority, and no U.S. President has ever suffered politically for his indifference to its occurrence. It is thus no coincidence that genocide rages on.” What’s past is prologue.