WASHINGTON – It's not just Johnny Depp.

It's not just Kathy Griffin.

It's not just Shakespeare in the Park in New York.

A pattern of assassination "jokes" directed at Donald Trump and violence and threats of violence against Republican members of Congress have turned American politics into a seething cauldron of unprecedented hatred prompting many observers to wonder what's next.

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Depp issued an apology Friday for asking the question: "When was the last time an actor assassinated a president?"

Speaking Thursday at the Glastonbury arts festival in southwest England, Depp asked the audience, "Can you bring Trump here?"

Chris Buskirk and Seth Leibsohn explain how the conservative elite, Washington insiders, and mainstream media were so completely out of touch with reality during the 2016 US presidential election cycle, in "American Greatness."

The remark was met with booing and jeering, and he continued: "You misunderstand completely. When was the last time an actor assassinated a president? I want to clarify: I'm not an actor. I lie for a living. However, it's been awhile, and maybe it's time."

In his apology statement, issued not to Trump, but to People Magazine, Depp said: "It did not come out as intended, and I intended no malice. I was only trying to amuse, not to harm anyone."

Depp's "joke," an allusion to the assassination of Abraham Lincoln by John Wilkes Booth in 1865, was made during an appearance at the Glastonbury Festival.

The White House issued a statement strongly condemning the joke and calling on others in Hollywood to speak out.

"President Trump has condemned violence in all forms and it's sad that others like Johnny Depp have not followed his lead," the statement read. "I hope that some of Mr. Depp's colleagues will speak out against this type of rhetoric as strongly as they would if his comments were directed to a Democrat elected official."

Depp is only the latest celebrity to find himself in hot water over violent commentary aimed at Trump. Late last month, Kathy Griffin posed for a photo shoot in which she held up a bloody prop head that resembled Trump. The comedian has also apologized, and was dropped from her co-hosting gig at CNN's New Year's Eve show.

On Friday afternoon, Sean Spicer, the White House press secretary, mentioned Depp and Kathy Griffin in responding to a question about a Shakespeare in the Park production of "Julius Caesar" that has drawn criticism from Republicans for depicting a Trump-like Caesar being assassinated.

Spicer said he didn't know if the president was aware of the play, but "whether it's that or Johnny Depp's comments," there is a "troubling lack of outrage we've seen in some of these incidents."

In January, Madonna, speaking at the Women's March on Washington, said that she'd "thought an awful lot about blowing up the White House."

In a TMZ video in 2015, Mickey Rourke, the boxer-turned-actor, called Trump a "big-mouthed b----- bully," saying he would "love 30 seconds in a room with the little b-----." Rourke has also expressed a desire to "give [Trump] a Louisville slugger."

In 2016, Larry Wilmore, the host of Comedy Central's now-canceled "The Nightly Show" joked about then-candidate Donald Trump: "I don't want to give him any more oxygen. That's not a euphemism, by the way. I mean it literally. Somebody get me the pillow they used to kill [Supreme Court Justice Antonin] Scalia and I'll do it — I'll do it!

In 2016, Mexican-American comedian George Lopez tweeted a cartoon image of former Mexican president Vincente Fox holding the decapitated head of Donald Trump aloft, with the caption "Make America Great Again."

Also, last year, shock-rocker Marilyn Manson released a teaser video for his song, "Say10," released just after the 2016 election, a Trump-like figure wearing a suit and a red tie lies decapitated on a concrete floor, in a pool of his own blood.

In February 2017, actor Robert De Niro said on ABC's "The View" that he would like to punch Trump in the face. He clarified earlier comments, saying "It wasn't like I was gonna go find him and [really] punch him in the face, but he's gotta hear it."

In March 2017, rapper Snoop Dogg released a music video that cast Trump as a clown and orchestrated his death. At the video's end, the "Gin and Juice" rapper points a gun at the harlequin Trump figure and shoots. But instead of a bullet, a red flag that reads "Bang!" fires out of the gun.

Earlier this month, the musician Moby released a cartoonish video in which a transformer-like Trump morphs into a swastika/dollar sign and wreaks havoc on a city before meeting a fiery, explosive demise.

Meanwhile, Hollywood director Josh Fox just blasted President Trump and Mitch McConnell in a tweet, calling them "terrorists" over the Senate version of the health care bill. It said the Obamacare replacement "sentences poor people to death." In April he made headlines for suggesting that that instead of bombing ISIS, the United States should love them instead, and end terrorism that way.

On MSNBC Thursday, Elise Jordan, a former Bush White House aide, warned Republicans against defending Trump, comparing doing so to "hugging a suicide bomber." The comments were in response to Trump's latest tweets undermining his previous statement hinting that he may have recorded tapes of his conversations with former FBI director James Comey.

Meanwhile, a total of 30 Republican members of Congress have either been attacked or revealed that they were the victim of a death threat since the beginning of May.

On Thursday, an audio recording was posted on YouTube of a Nebraska Democratic Party official saying he was glad Rep. Steve Scalise, R-Louisiana, was shot last week. Phil Montag, a technology chairman for the party, was fired for saying: "His whole job is to get people, convince Republicans to (expletive) kick people off (expletive) health care. I'm glad he got shot. I wish he was f***ing dead."