The day the Mueller report was released, President Trump said he might stay in the Oval Office "at least for 10 or 14 years." Trump, fearing "bedlam" over this remark, said it was a "joke," similar to the one he made last year when he expressed interest in being "president for life."

Trump loves to joke around. His wit is so subtle, so nuanced, that sometimes it takes years to decipher it, along with a spokesperson to clarify it.

Earlier this month, White House press secretary Sarah Sanders said that Trump "was making a joke during the 2016 campaign" when he said, "I love WikiLeaks." Her clarification came three days after Julian Assange, the founder of WikiLeaks, was arrested and three years after Trump made the "joke."

Everyone knows that a joke is not a joke if it has to be explained. With Trump, the inverse is true: When he says something that he can't explain, it becomes a joke. His statements become jokes retroactively, when they become inconvenient.

In 2017, the president of the United States implored police officers to beat up suspects. After the New York Police Department and the president of the Major Cities Chiefs Association released statements rebuking his comments, Sanders said, "He was making a joke at the time."

Similarly, when Trump accused Democrats of treason for not clapping for him at his State of the Union address, he was, Sanders said, "clearly joking with his comments." (No word yet on whether Trump was joking when he tweeted earlier this month that Democrats were "TREASONOUS.")

When Trump thanked Vladimir Putin for expelling American diplomats from the U.S. Embassy in Moscow, he was being "tongue-in-cheek," according to a then-Rep. Ron DeSantis (R-Fla.).

Trump "made a joke" when he challenged former Secretary of State Rex Tillerson to an IQ test. "Maybe you guys should get a sense of humor and try it sometime," Sanders told reporters.

(Neither Sanders nor Trump, who thinks Saturday Night Live deserves "retribution," nor any other administration staffers attended this year's White House Correspondents' Dinner, an annual event traditionally featuring a professional comedian telling jokes.)

After Trump said that Americans should sit up at attention when he speaks, he told a reporter he was "kidding. You don't understand sarcasm."

But Trump's sarcasm is not easy to discern. It's not sarcasm if you really mean it. He says he was "sarcastic" when he said at a press conference in 2016, "Russia, if you're listening, I hope you're able to find the 30,000 emails that are missing." Russian hackers, unable to detect Trump's sarcasm, attempted to do just that within five hours of Trump's sardonic request, according to the Mueller report.

After Trump said, on multiple occasions, that Barack Obama was "the founder of ISIS," Hugh Hewitt said Trump was being metaphorical, Breitbart said Trump was "literally" correct, and Trump said he was being "sarcastic but not that sarcastic," which was a way of recanting and repeating his slur at the same time.

We never know if Trump means what he says, and neither does he. There are as many interpretations of his words as there are words in his vocabulary. His speech is performative, as even he acknowledges. At CPAC this year, Trump told the audience, "Our great first lady always said, 'Don't use certain words, please.' I said, 'But the audience wanted me to do it.'"

When certain words come back to haunt him, he claims he didn't mean them. Retroactive sarcasm gives him plausible deniability — a way to make shameless statements without being held accountable for them. If Congress impeaches Trump for obstruction of justice, no doubt his lawyers will say that he obstructed justice sarcastically.

In his book Talk Is Cheap: Sarcasm, Alienation, and the Evolution of Language, Professor John Haiman describes this tactic as "a kind of self-protective and preemptive self-abasement, comparable to the submissive posture of dogs and wolves in the presence of the alpha male." Implicit in every word Trump utters is a meta-message: "I don't really stand by this; confronted by opposition I will cut and run... You thought I was serious? Ha ha!"

Other provocateurs use this same excuse. Milo Yiannopoulos claimed he "wasn't being serious" when he said he couldn't wait for "vigilante squads to start gunning journalists" just days before a gunman killed five journalists last year.

You can't have it both ways. You can't incite violence, lie, and insult people and then claim comedic immunity, especially when you aren't funny. Trollery is not drollery.

Trump can't take a joke or tell one. When he said he was running for president, millions of people took him seriously.