An ancient concept honored by civilized nations for centuries, diplomatic immunity is guaranteed under the 1961 Vienna Convention on Diplomatic Relations, agreed to by virtually every country in the world.

But sometimes it’s wrong for a nation to stand on its rights.

We’re thinking, of course, of the case of Anne Sacoolas, the wife of a US diplomat based in England who fatally hit 19-year-old Harry Dunn while driving on the wrong side of the road on Aug. 27, admitted her role at the scene — but soon fled back home.

She is covered: A 1994 US-UK agreement specifically grants diplomatic immunity to Americans stationed, as the Sacoolases were, at the Croughton air base. The question is whether she should stand on her privilege — and whether the Trump administration should waive immunity in this instance.

Immunity is supposed to protect diplomats from harassment by host governments, not grant them impunity to flout local laws. Here in the city, UN diplomats’ ability to run up fortunes in parking and traffic fines is a longstanding irritant. Even drunk drivers escape justice.

And homicide, even accidental, of an innocent is another matter. Dunn’s parents are begging Sacoolas to return so they can find closure, and London is asking Washington to waive immunity in this case.

A waiver wouldn’t expose Sacoolas to some kangaroo court but to the legal processes of another strong rule-of-law nation. And London waived diplomatic immunity just last year in the case of Youssef Amrouche, who was charged with beating his diplomat wife here in the city.

The letter of international law may protect Anne Sacoolas, but the spirit of decency is calling for her to face justice.