United Nations Ambassador Nikki Haley has laid down an important marker to Donald J. Trump.

Do not diss me in public; do not subject me to public humiliation; I will not take it quietly.

Haley, one of the few grownups in the Trump administration’s inner circle, spoke out recently in which she suggested the United States would impose additional sanctions on Russia as punishment for its complicity in the gassing of Syrian civilians.

Then she got her humiliation handed to her by Lawrence Kudlow, the president’s newly appointed national economics adviser. Kudlow suggested that Haley got “ahead of the curve” and might have suffered from some “confusion” over a policy that had been changed without her knowledge.

That is not tolerable to Haley. Nor should it be.

She has referred to Russian meddling in our 2016 presidential election an “act of warfare.” She has clashed with other senior Trump Cabinet officials. She has stood her ground.

But now she has drawn her own “red line,” letting the president know that she won’t stand for being called out in the manner she was by Kudlow.

I happen to be in Haley’s corner on this matter.

As this nation’s ambassador to the United Nations, she needs to be kept in the loop at all times on all policies being pondered by the Policy Maker in Chief … the president. Then again, the president needs to show at the very least a sliver of discipline as he blunders through this and/or that crisis, or makes this and/or that policy pronouncement.

Whenever he tweets a policy statement, only to take some or all of it back, the president puts the precious few grownups he has brought on board in a serious diplomatic pickle. Heaven knows that the president has brought damn few competent individuals on board.

One of them, Nikki Haley, deserved far better than she got.