When Donald Trump moved into the White House on January 20, 2017, he brought with him a whole host of reasons why he should not be president. One was his unprecedented business entanglements, which present potential conflicts of interest on a near-daily basis. Another was his famously not great temperament, which, combined with his penchant for lashing out on Twitter at everyone from Angela Merkel to Jimmy Fallon to “lowlife” former employees, makes him a whiplash-inducing diplomatic partner. There’s also the minor matter of him being a magnet for corruption, suspiciously deferential to the Kremlin, and quite possibly a racist (a charge he has vehemently denied). Putting all of that aside, though—and yes, that’s a lot to put aside!—there’s still one major obstacle preventing him from doing an effective job running the most powerful country in the world: the fact that he’s a total moron. That Trump is not very bright, despite claiming to be “like, really smart,” is an issue that has come up frequently during his first year and a half in office, leading him to commit numerous gaffes, such as the time he claimed health insurance costs $12 a year, or when he suggested Frederick Douglass, the famous abolitionist and activist born in 1818, was still alive. But a new report from Politico lays bare just how little the self-described “stable genius” understands about elementary concepts such as:

Time zones: According to reporter Daniel Lippman, White House aides are compelled to explain, on a “constant basis,” why Trump can’t call, say, the Prime Minister of Japan when it’s 4 in the afternoon in Washington. “He wasn’t great with recognizing that the leader of a country might be 80 or 85 years old and isn’t going to be awake or in the right place at 10:30 or 11 P.M. their time,” a former Trump N.S.C. official told Politico. “When he wants to call someone, he wants to call someone. He’s more impulsive that way. He doesn’t think about what time it is or who it is.”

Identifying countries: “He didn’t know what those were,” said one person familiar with a meeting in which Trump reportedly could not identify Nepal and Bhutan, which are in between China and India. “He thought it was all part of India. He was like, ‘What is this stuff in between and these other countries?’”

How to pronounce words: During the incident wherein Trump seemingly heard about Nepal and Bhutan for the first time, he reportedly pronounced Bhutan as “button” and Nepal as “nipple,” a classic mix-up! During public remarks, the president has also referred to Namibia as “Nambia,” but White House officials were very proud of one of his conquests: “He did a very good job of saying Côte d'Ivoire,” an aide told Politico.

Which countries have beef with each other: During one of his meetings with Japanese Prime Minister Shinzo Abe, Trump “repeatedly praised Chinese President Xi Jinping,” said a former N.S.C. official from a previous administration. “Everyone was cringing because Japan and China are rivals, and the Japanese and the Chinese are nervous about the president tilting too far towards the other side,” that person said.

Which jokes cross the line: Before Indian Prime Minister Narendra Modi visited Washington in June 2017, Trump reportedly asked whether his wife was coming along, too—prompting a quick lesson on Modi’s marital history. When he learned that Modi had been estranged from his wife for years, he reportedly joked, “Ah, I think I can set him up with somebody.”

That presidents don’t call each other just to shoot the s--t: While more qualified heads of state understand that world leaders call each other 1) having prepared first, and 2) with a specific purpose, President Flip-Phone apparently dials people up whenever the mood strikes. “The standard is you don’t have your principal call unless you’re asking for something or trying to reward a behavior, either a carrot or a stick. You don’t just randomly call,” a former official said. Apparently, French President Emmanuel Macron was most often victimized by this particular piece of ignorance on Trump’s part. “He wanted to talk to him constantly. . . . Macron would be like: ‘Hey, what are we talking about?’ These are very busy people. You don’t just call to check in,” the official said.