"I was just so excited to hear he was upset about it, because it feels like comedy is a weapon that we can use against them, that they don't have," said standup comedian Nikki Glaser, who doesn't support Trump.
McCarthy lampooned one of the most visible members of Trump's White House, one who already faces scrutiny by the president himself. Trump watches Spicer's press briefings and summons him later in the day for praise and criticism, the New York Times reported, citing a West Wing aide.
Image matters to Trump. Per that same Times story, Trump has directed staff to hold as many events as possible in the Oval Office, where he is obsessed with the decor. The window dressings were changed to gold curtains on Day One of his presidency. He's used the phrase "central casting" to describe generals, potential running mates and possible Cabinet secretaries. During the transition, he sought to fill the most visible administration roles with not only those who can do the job, but people who also look the part.
"Presentation is very important because you're representing America not only on the national stage, but also the international stage, depending on the position," Trump transition spokesman Jason Miller told The Washington Post in December.
Alec Baldwin's portrayal of Trump on SNL got under his skin when he was a candidate, a president-elect and now as president. Trump has repeatedly discussed and tweeted about Baldwin's impersonation, calling it mean-spirited and biased.
Late-night comics lampooning a president is nothing new, particularly on SNL. The NBC show has done a better job with some White House occupants than others, but if any other heads of state were upset by these portrayals, they kept their criticism private.
Not Trump. And this signals an opening for professional comics opposed to his agenda.
"This is the world's greatest roast with the most serious consequences in the history of our country," said longtime standup comic Andy Kindler, who roasts the comedy industry in an annual address at the Just For Laughs festival. "This is a classic situation where the more the target shows weakness, the more the target needs to be prodded. That's why I think Alec Baldwin is having the time of his life."
"His comebacks are so weak," Kindler added of Trump. "I hope it keeps going. I hope it makes him resign."
For Trump, the most problematic aspect of the SNL Spicer sketch was that a woman played Spicer, according to Politico. As a top Trump donor told the outlet, "Trump doesn't like his people to look weak." This speaks volumes about Trump's concept of weakness and strength - particularly since the cross-gender casting isn't what made the "Sean Spicer Press Conference" go viral. It was because the sketch was incredibly funny, thanks to McCarthy's comedic mastery.
"I literally couldn't believe, just on a technical level, how brilliant it was," said Kindler. "Even if he had thick skin, it would have affected him because it was just so devastating."
SNL has always had a wide audience, which likely helped the sketch cross beyond any confines of a liberal bubble. The show is having its strongest ratings in 22 years, with this season drawing in an average of 10.6 million viewers, according to preliminary numbers reported by Variety.
Plus, the Spicer sketch was just high-quality comedy.
"It was just so strong comedically: her performance, the writing, and it permeated through both sides," Glaser said. "If it's funny enough, it'll get through, and I think that's the balance you have to strike."
McCarthy has a track record of playing angry characters well. On Saturday, she showed her comedic prowess in a live sketch that stretched beyond seven minutes and combined wild gesticulations, yelling and prop comedy all while embodying a character so effectively that many audience members at first didn't recognize who was under all that hair and makeup.
Trump's focus on the cross-gender casting shows he may have missed the joke, one about a White House spokesman making hilariously illogical defenses and shouting down reporters.
"He can't laugh it off. He doesn't get comedy - it's being misinterpreted by him, but it's great it's angering him so much," said Glaser.
The Spicer sketch also showed the comedic potential to joke about politics beyond just Trump. Kindler recalled the Watergate scandal and how the jokes moved beyond Nixon to include people like his chief of staff, H.R. Haldeman. "The more intense it gets," Kindler said, "the more familiar you get with these people."
But this dynamic, of jokes affecting Trump, is a double-edged sword for those who stand opposed to the president. He could react in ways they don't want.
Glaser pointed to President Barack Obama's jokes at the 2011 White House Correspondents' Association dinner about a possible Trump presidency. Some believe this may have inadvertently encouraged him to run for president, although it's a narrative Trump has denied.
"Comedy got us into this," she said. Still, "there are bullies on their side, but we can bully them with comedy - it's just outsmarting them with comedy."
