With apologies to Rud­yard Kipling, “If you can keep your head when all about you are losing theirs . . .” you are Donald Trump. At least that was the case Tuesday.

With Democrats going mad, Republicans going wobbly and the media mob acting like a lynching party, it was left to the president to call bulls–t on the Brett Kavanaugh allegations — and remind the nation of the enormous stakes involved.

On a normal day, in a saner world, Trump’s tough-love speech at the United Nations would deserve our full attention. It was a comprehensive outline of his America First doctrine, but the elephant in the room is that America cannot lead the world when it is unraveling at home.

And so the president stepped away from the General Assembly and onto the bully pulpit to forcefully denounce the partisan attacks on his Supreme Court nominee as a “con game.” He accused Dems and, by extension, the media of playing “a very dangerous game” by instantly embracing every charge as gospel.

This is about whether there are any boundaries left in our politics. Or whether this is a war where anything goes and the goal is the total annihilation of the other side.

Trump made no mention of fellow Republicans, but didn’t need to. His aggressive and at times angry pushback amounted to a certain trumpet call for GOP senators to stiffen their spines and stop the hand-wringing.

Yet the larger significance of Trump’s comments was not about the hazy claims of the two accusers or counting votes in the Senate. This was at heart a plea for simple decency at a moment when it appears headed for extinction.

That the plea came from Trump makes it easy for the left to mock it, as they mercilessly did when they didn’t ignore it altogether. But this is not about him, or shouldn’t be, nor is it just about the makeup of the Supreme Court, as important as that is.

This is about whether there are any boundaries left in our politics. Or whether this is a war where anything goes and the goal is the total annihilation of the other side.

The president cited the toll on Kavanaugh’s family as Exhibit A of the damage already done. Probably referring to the appearance of the judge and wife Ashley on Fox News Monday, where they both looked shocked and wounded, Trump said, “His wife is devastated, his children are devastated. I don’t mean they’re like, ‘Oh, gee I’m a little unhappy,’ they’re devastated.”

That could be any family sitting there, their world savagely ripped open because they dared to excel in their field and sacrifice material riches for the honor of public service. As Trump said, if Kavanaugh is kept off the high court on charges that go back more than 30 years and that have no known proof or corroboration, “it’ll be a horrible, horrible thing for future political people, judges, anything you want, it’ll be a horrible thing. It cannot be allowed to happen.”

Unfortunately, it is happening, which is why the president was right to drop his earlier more respectful tone toward the accusers and Dems. Being polite gets you nowhere with a wolf pack, and good faith is meaningless when the aim is complete character assassination.

The coercive, intolerant rabble running left-wing politics could easily lead to serious violence. The thuggish activists who are driving Republicans out of restaurants and other public spaces are crossing lines of acceptable conduct that have been respected for the better part of two centuries.

The latest case involves Sen. Ted Cruz and his wife, who were hassled so much that they left a Washington restaurant Monday night.

The group of self-described anarchists, socialists and sexual-assault survivors targeting them later released a threatening statement that read in part, “This is a message to Ted Cruz, Brett Kavanaugh, Donald Trump and the rest of the racist, sexist, transphobic, and homophobic right-wing scum: You are not safe. We will find you. We will expose you. We will take from you the peace you have taken from so many others.”

That threat should send chills down the backs of every American, and should unite all of Washington around the need for a time-out. Yet not a peep is heard from Chuck Schumer and the Senate Democrats who are orchestrating the attacks on Kavanaugh and thus spurring such open expressions of hate and vows of physical assault.

What country are we in? What country are we becoming?

For conservatives, the answer is not to respond in kind. The answer is to summon the courage to stand up for what is right. And not to worry about the next damn election.

It starts with Kavanaugh. If serious allegations emerge that are provable and corroborated at Thursday’s hearing, his nomination should be defeated or withdrawn.

But no such allegation has emerged yet, and his denials have been consistent and complete. On the basis of what we know, he is superbly qualified to sit on the Supreme Court and should be confirmed.

To do less and to fold out of fear is to appease outrageous conduct in the false hope the wolf will be happy with one meal. History proves otherwise and shows that those who won’t take a stand will get their turn on the menu.

Click here to keep reading Michael Goodwin's column in the New York Post.