More than a century later, the 45th president of the United States seems to be reworking President Theodore Roosevelt famous aphorism: “Speak softly and carry a big stick; you will go far.”

"Scream loudly about the size of your stick, and see how far that goes," could easily be President Donald Trump’s governing epigram, with that approach on display most recently in the letter he released Thursday cancelling his planned summit with North Korean leader Kim Jong Un.

Given the stakes and personalities involved, however, Trump’s low-thought, gut-heavy approach could well also provide his administration’s epitaph — and that of a lot of others.

“You talk about your nuclear capabilities, but ours are so massive and powerful that I pray to God they will never have to be used,” Trump wrote, one of the White House pronouncements that seems to carry the ring of authentic Trumpism (though perhaps with a touch of John Bolton’s mustache tickling the presidential ear). The statement was complete with the great man’s meandering syntax: “Therefore, please let this letter serve to represent that that the Singapore summit, for the good of both parties, but to the detriment of the world, will not take place.”

The withdrawal had the Trumpian touch on the substance as well, given his love of the dramatic gesture which then, potentially, can set up some sort of compromise. “Threaten the outrageous, ratchet up the tension, amplify it with tweets and taunts, and then compromise on fairly conventional middle ground,” Axios’ Jonathan Swan summed it up last month in a piece that, tellingly, also paraphrased Trump associates as calling him “a one-trick pony in negotiations.”

It’s part of Trump’s apparent embrace of the old Nixonian “madman theory” of global politics: Try to convince the rest of the world that the leader is erratic enough that you just don’t know what he’s going to do next. (Consider, too, that candidate Trump's central complaint about U.S. foreign policy was “We are totally predictable. …We have to be unpredictable, and we have to be unpredictable starting now.”)

But when the madman is a one-trick pony, the approach falls apart. “The world learns to ignore Trump,” was the headline on a Politico story last month, noting that reactions to the president’s peripatetic pronouncements are producing diminishing returns in terms of global reaction. “All of this has led investors, executives and diplomats to the conclusion that trying to act on any single thing Trump says or tweets is a fool’s game,” they reported. Of course one can’t precisely ignore the bully at the pulpit — stocks dropped more than 200 points with Trump’s announcement Thursday before starting to slowly inch back up — but that everyone else is catching on to Trump’s shtick is clear. (See, for example, Trump’s trade-war pause with China.)

When the madman is a one-trick pony, the approach falls apart.

And the technique is potentially dangerous. One possible reaction to Trump's cries of wolf getting ignored would be for him to make increasingly brash and extravagant claims and threats, to try to appear even crazier.

Another key difference between Trump's approach and Nixon's was that Nixon undergirded his act with a wonk’s grasp of fact, detail and personalities. There are many complaints to be leveled about Tricky Dick, but smug laziness is not among them. The same cannot be said of Trump. Numerous reports have portrayed a commander-in-chief uninterested and unwilling to do the prep work which summits typically entail. Trump “has been almost singularly focused on the pageantry of the summit — including the suspenseful roll-out of details,” the Associated Press’ Catherine Lucey and Zeke Miller reported earlier this week, for example. “He has not been deeply engaged in briefing materials on North Korea’s nuclear program.”

Of course Trump, the reality TV president, has been more engaged in the pageantry: He’s an optics-and-narrative president, not a details guy. And despite Secretary of State Mike Pompeo telling the Senate Foreign Relations Committee Thursday that “it’s not about the deal, it’s about the outcome,” it has been clear for some time that, for Trump, it’s about the deal.

Seat-of-the-pants diplomacy is fraught under the best of circumstances. But it is a regular, tiring and scary part of surreal world through we are now careering.

It’s about being able to brag — truthfully, for once — that through his legendary (many would say mythical) deal-making skills, he accomplished what his better-credentialed predecessors could not. For a while he fancied he might do this in the Middle East (after all, he put top men like Jared Kushner on the case) but even Trump seems to have given up that fantasy. And so he became entranced with North Korea, a vexing problem complete with what every good television drama needs: An arch-villain with whom the president could heroically match wits.

So he jumped at the bait that his pointy-headed predecessors had abjured and agreed to a no-concessions meeting with the Kim. He acted with such haste and so little planning that the kind of lower-level diplomatic spadework which usually precedes these kinds of meetings reportedly remained largely unfinished just weeks before it was supposed to take place. (But they did get the important stuff done like minting commemorative coin, which was suddenly for sale at a discount Thursday.)

In recent days and weeks, he and his team have reportedly started to become concerned that he seemed too eager to deal and that the summit could well turn into a PR victory for Kim. Those concerns may have informed Trump’s decision to pull out of the summit while inviting North Korea to come begging for a restart.

Seat-of-the-pants diplomacy is fraught under the best of circumstances. But it is a regular, tiring and scary part of surreal world through we are now careening, with two nuclear-armed, impulse-control-deficient man-children regularly comparing the sizes of their arsenals while trading insults (Mike Pence is a “political dummy,” per North Korea, after he echoed administration threats of the “Libya model” of denuclearization, which Libya’s leader did not survive). The result Thursday was a you-can’t-dump-me-because-I’m-dumping you epistle. Who knows what it will be tomorrow and the day after.

We can only hope that the fury is worse than the fire.

Robert Schlesinger is a veteran Washington journalist and commentator. He is the author of “White House Ghosts: Presidents and Their Speechwriters.”