1 big thing: Trump, the "crazy guy"

In an Oval Office meeting earlier this month, President Trump gave his top trade negotiator, Robert Lighthizer, an Art of the Deal-style coaching session on how to negotiate with the South Koreans.

Trump's impromptu coaching came in the middle of a pivotal conversation with top officials about whether or not to withdraw from the U.S.-Korean trade deal. Sources familiar with the conversation paraphrased the exchange for Axios, and the White House did not dispute this account.

A number of senior officials and cabinet secretaries were present for the conversation, including Defense Secretary Mattis, Agriculture Secretary Perdue, and Secretary of State Tillerson. At issue was whether the U.S. would withdraw from the Korean trade deal — an action Trump threatened but still hasn't taken.

"You've got 30 days, and if you don't get concessions then I'm pulling out," Trump told Lighthizer.

"Ok, well I'll tell the Koreans they've got 30 days," Lighthizer replied.

"No, no, no," Trump interjected. "That's not how you negotiate. You don't tell them they've got 30 days. You tell them, 'This guy's so crazy he could pull out any minute."'

"That's what you tell them: Any minute," Trump continued. "And by the way, I might. You guys all need to know I might. You don't tell them 30 days. If they take 30 days they'll stretch this out."

"You tell them if they don't give the concessions now, this crazy guy will pull out of the deal."

Why this matters: Plenty of world leaders think the president is crazy — and he seems to view that madman reputation as an asset. The downsides are obvious: the rhetoric can unnerve allies and has the potential to provoke enemies into needless, unintended war. But Trump keeps using the tactic, with varying degrees of success:

Just today, the president undercut his secretary of state by suggesting diplomacy with "Little Rocket Man" in North Korea was a waste of time — implying that only military action would resolve the conflict. "Save your energy Rex," Trump tweeted, "we'll do what has to be done!"

Later in the afternoon Trump tweeted: "Being nice to Rocket Man hasn't worked in 25 years, why would it work now? Clinton failed, Bush failed, and Obama failed. I won't fail."

We've never seen anything like this before with a president and his secretary of state. Trump's tweet, undercutting Tillerson's diplomatic efforts, comes a day after Tillerson acknowledged for the first time that the administration was in direct communication with North Korea.

Trump's tweet also undercuts a statement made Tuesday by Joint Chiefs Chairman General Dunford: "The military dimension today is in full support of the economic and diplomatic pressure campaign the secretary of state is leading in North Korea."

Trump's comments today belong to a pattern that fits the "madman" or "he might just be crazy enough to do that" theory of international relations:

Trump warned North Korean leaders in August that if they keep threatening the U.S., they "will be met with fire and fury like the world has never seen."

In his first speech to the U.N. General Assembly, Trump threatened to "totally destroy North Korea" and called Kim Jong-un "Rocket Man."

He threatened over Twitter to withdraw from the North American Free Trade Agreement: "We are in the NAFTA (worst trade deal ever made) renegotiation process with Mexico & Canada.Both being very difficult,may have to terminate?"

He unnerved America's allies during the campaign when he called NATO "obsolete" and refused to say whether he'd defend a treaty ally under attack from Russia. Trump has spoken more favorably of NATO since becoming president, but he still often complains about NATO members failing to pay their fair share, and he's urged Angela Merkel to increase Germany's military budget.

Go deeper: Insight on the president's "crazy" approach from senior administration officials and top national security personnel.