Sooner or later, every president experiences fleeting feelings that he's somehow accomplished the geometrically impossible feat of painting himself into a corner of his Oval Office.

Along with the Marine band's ceremonial "Hail to the Chief" and the military aide toting the nuclear-code "football," feelings of entrapment come with the job.

But these days, Donald Trump is looking, sounding and behaving as if he's feeling like those white oval walls are closing in, a little more each day. Well, maybe they are.

After all, Trump's White House just reportedly received a list of written questions from special counsel Robert Mueller for the president (and his legal team) to answer. Clearly, Mueller's probe into whether Trump's team was involved with Russia's efforts to cyber-sabotage America's democracy in Campaign 2016 or beyond is in its final stages.

No wonder "Mueller" seems to pop up so often when Trump starts rambling about matters unrelated to the special counsel's work. And that's just what happened when Trump sat down Wednesday for what he correctly assumed wound be an unchallenging respite with journalists from the conservative Daily Caller website.

In question after question, according to The Daily Caller's published transcript, Trump wound up careening off-topic, sometimes in streams of consciousness that seemed worthy of a new Monty Python epic.

As when a Daily Caller interviewer asked about immigration and whether Trump was willing to shut down the government if Congress didn't give him what he wanted.

"I may very well be willing to shut down the government," Trump said. "I think it's horrible what's happening and, you know, building the wall, it's in smaller stages, we can build it very quickly. I'm building the wall in smaller stages and we moved the military there, we put up barbed wire. … You have to have a barrier. Look, we have a chance of, they can do presidential harassment, put very simply, and I'll be very good at handling that and I think I'll be better than anybody in the history of this office. … I actually think it's good for me politically, because everyone knows it's pure harassment. Just like the witch hunt, the Mueller witch hunt. It's pure harassment. It's horrible. It's horrible that they're allowed to get away with it.

"Again, not Senate confirmed but, you know. You have 17 people, half of them worked for Hillary Clinton, some on the Foundation. The Hillary Clinton Foundation. I mean, you think of it. So, I think we'll do very well if they want to play the presidential harassment game."

That's just how he said it – careening from immigration to Mueller, Hillary and harassment.

When the interviewer asked if Broward County election commissioner Brenda Snipes is "behaving criminally and should she be removed?" Trump said "she's a disaster" – then launched into a nationwide set of conspiracy assertions.

Unfortunately Trump's interviewers didn't ask what he was talking about. Or if he ever had or saw any proof.

Asked if he is "happy" with his new acting Attorney General Matthew Whitaker, Trump said Whitaker was "very respected," But then he veered back onto his old Mueller trail.

"And, um, you know, look, as far as I'm concerned this is an investigation that should have never been brought," Trump said. "It should have never been had. It's something that should have never been brought. It's an illegal investigation. And you know, it's very interesting because when you talk about not Senate confirmed (which nobody had mentioned), well, Mueller's not Senate confirmed. … He's heading this whole big thing, he's not Senate confirmed."

But don't jump to conclusions. None of the above means America's 45th president is panicked and has lost touch with reality. After all, Trump is the only one who really knows all that happened – all that Mueller is determined to discover.

Trump may be the most solidly grounded guy in Washington when it comes to anticipating tomorrow's reality.

– Martin Schram, a columnist for Tribune News Service, is a veteran Washington journalist, author and TV documentary executive. Readers may send him email at martin.schram@gmail.com.