Turns out there’s one more thing we can count on besides death and taxes – that whenever Donald Trump opens his mouth it’s a sure thing that it won’t be long before he puts his foot in it.

Sometimes it’s his dishonesty; he makes a claim that is demonstrably untrue, and very often there’s video to prove how untrue it is. Or sometimes it’s his narcissism; bragging about how his TV ratings were better than Arnold Schwarzenegger’s — at a National Prayer Breakfast no less, to cite just one example. Or sometimes it’s his disloyalty, the things he says about people who have shown great loyalty to him.

As I write this, his target is Jeff Sessions, the attorney general, though there may very well be a new target 10 minutes from now.  It’s one thing to go after a political enemy – but a friend?

Jeff Sessions, as everybody including Donald Trump knows, was an early supporter of Mr. Trump when no one thought he had a chance of winning the nomination; when every other GOP senator wouldn’t touch the guy with a 10-foot pole. Memo to POTUS: You’re not humiliating Jeff Sessions with your non-stop cheap shots. You’re humiliating yourself.

And there’s something else about this president: He’s not nearly as smart as he thinks he is.

Despite his Ivy League education, he still hasn’t figured out that he’s no longer running a relatively small company out of Trump Tower on Fifth Avenue in Manhattan.

When he was Businessman Trump his word was the law. He had no board of directors to answer to and no stockholders to please. He could be the king of his domain and get away with it.

But he’s not the king anymore; though I’m not at all sure he understands that. Being president requires collegiality, a Reagan-like optimism, an understanding of how to get things done when you can’t simply issue a decree — qualities in short supply with this president.

It’s not exactly a bulletin that Donald Trump has plenty of enemies. But another thing he doesn’t quite seem to grasp is that he doesn’t have the kinds of friends he really needs.

He needs to pretend that his most loyal followers — the ones who love anything and everything he does – don’t exist. Instead of throwing them red meat – whether it’s about “fake news” or Crooked Hillary (he can’t let that one go either) — he needs to ignore them. They give him a false sense of security.

If he doesn’t build the wall, he’ll still have his base. If repeal and replace goes nowhere, he’ll still have his base. If there’s no tax reform or infrastructure legislation, he’ll still have his base. They’ll blame obstructionist Democrats and “squishy” Republicans for any and all failures. But they won’t blame Donald Trump. Acolytes don’t blame the ones they worship.

But we understand why he continues to toss them the red meat that they love. It’s because he needs their adoration, their adulation, the way most of us need oxygen. Without it he can’t survive.

But they’re not his friends. Friends hold friends accountable when they do stupid things. Friends don’t let friends blow up their presidency.

President Trump’s approval ratings stink, to use a technical term. And they’re not going to get better by simply appealing to his base. What the base loves about him, most Americans don’t.

That’s because the Donald Trump’s most loyal supporters are not like most Americans. They’re angrier and more alienated. They believe they’re losing the America they grew up in and they don’t like it. And they sense that Donald Trump, the tough guy who doesn’t care what anybody thinks, understands them in a way that most politicians don’t — and never really have.

And he’ll remain their kind of guy even if he fires Sessions … and then dumps the deputy attorney general … and after that the special counsel who seems to make the president nervous. But if he does any of that, his days will be numbered.

Yes, he’ll still have his base. But that’s all he’ll have. And that won’t be nearly enough to make America great again. It might not even be enough to stay in office for his entire term.