POTUS coming to Tuesday lunch.

Translated, the president of the United States is joining 50 Republican senators in the Capitol to crash their private Tuesday lunch. Nobody is glad to hear this on the Senate side. We love the constitutional separation of powers. The Senate is the last citadel of democracy, they say.

We in the press are free as birds here on the Hill, compared to the cramped Dickensian quarters of the White House press corps. Except when the hungry bear comes around and looks like he’d eat us for lunch.

But Donald Trump is on the menu and he’s not looking for love. He’s not there to ask after the missing 51st Republican senator, John McCain, suffering a rare brain tumor.

Let’s steal into the ornate room and anticipate the one-way conversation. Here’s a few broad brushstrokes of how the Senate lunch is likely to go down.

Quickly, it's clear Trump is not there to consult on foreign policy in the Middle East. He knows best for Israel and Iran: He loves one and hates the other, simple as that. Bloodshed in Gaza at the American embassy opening in Jerusalem? Gimme a break.

It's safe to say Trump has a reckoning in mind at the one-year mark of the Russian investigation. The probe, led by special counsel Robert Mueller, into Russian hacking and influencing the 2016 election pecks at his head and haunts his tweets. It's the logical catalyst for the visit. His lawyers are girding for a long summer, but they tell him he can win this rumble. We're street fighters from New York.

Pause for a tirade against soft-spoken Jefferson Sessions, his attorney general and most ardent fan in the Senate. He recused himself from the Russian investigation which Trump cannot comprehend. Didn't Sessions know he was there to protect him from what's happening now? Hiring him was the biggest mistake, the only mistake, I made.

In his usual brutal style, Trump may deliver a missive for the 2018 cycle. Everything’s so great except for that “collusion” investigation. There is no collusion! In so many words, he’ll tell senators that he expects absolute loyalty always when they’re out in their states on the stump. Or else they will be — “Fired!”

His voice rising, Trump could threaten to campaign against and crush anyone who speaks a word against him. He will do it, too, without a moment’s notice, breaking glasses of tradition. They know it and that is why they sit silently with their white cloth napkins folded in their laps.

Once the Grand Old Party, the Republicans succumbed to the president’s dark “personalismo” politics, defined as the practice of glorifying a single leader. The party is there to serve him, not the other way around.

There’s no love — or even like — lost between the president and anybody in the room. More than any American president in history, Trump’s an interloper in his party.

Telegenic Jeff Flake, R-Ariz., the only one who denounced Trump on the floor, might run late for the date. Trump would taunt him for not running again.

Other than that, folks, Gina (Haspel) is going to be fantastic at the CIA. And Mike (Pompeo) at State said the allies would be mad at me if we ditched the Iran deal. I’m like, really? Let’s do it!

Cue to tape on how much Trump hates anything with Obama’s name on it, like Obamacare. Thunder and fury cross his face. McCain saved Obamacare by one vote and forbade Trump to attend his funeral.

For dessert, Trump declares that when he and Kim Jong Un win the Nobel Peace Prize, he’ll deserve it more than Obama.