President Donald Trump’s critics fixate on his tweets and then wonder why he spends so much time responding to their attacks. But why do they devote so much attention to his tweets in the first place? Maybe they realize that many Americans are happy to finally have a president who fights back.

The Left complains about how badly Republicans treated President Bill Clinton. But he disgraced himself in the Oval Office. And as America’s top elected official, he committed the crime of perjury.

Democrats also whine that conservatives said terrible things about President Barack Obama. But just look at his record.

He nationalized health care — a sixth of the economy — and in the process undermined the greatest medical care system in the world. He sent America into retreat overseas, with disastrous consequences. He used the IRS to harass his critics. He held no one accountable for the murder of Americans in Benghazi. He increased the national debt by $9 trillion. What good was there to say about him?

Finally, the Left is indignant about the horrible treatment — the usual litany of “isms” — shown Hillary Clinton. Yet her scandals run the gamut from Whitewater and sketchy cattle trades to Benghazi and hidden emails. The shameless type of self-dealing evident with the Clinton Foundation first surfaced with the firing of the White House travel staff when her husband became president. Yet, who but conservatives were willing to point out her misconduct?

President Trump hasn’t behaved like any of them. His only offense is being unusually candid for a politician.

Obviously, people are free to criticize the president. And, no doubt, if you’re a progressive or liberal, you don’t like what he’s doing: Appointing a solid constitutionalist to the Supreme Court. Restoring U.S. leadership abroad. Returning justice to the Justice Department. Securing America’s borders. Addressing the damage done by Obamacare.

Fixing Barack Obama’s mistakes is hard work. And the president is making a difference.

Which probably explains the Left’s truly unconscionable behavior. Its ranks aren’t content to claim that the Trump administration’s policies won’t work. They applaud the idea of violence against America’s president.

Forget the antics of the MSNBC morning show. The hosts are dishonest and shrill, but that’s standard fare in today’s mainstream media. What’s amazing are the vile attacks magnified by supposedly establishment journalists.

And consider the Hollywood personalities who take themselves so seriously they need to tell everyone what they think.

Last month, actor Johnny Depp asked a crowd, “When was the last time an actor assassinated a president?” He added, “It’s been awhile, and maybe it’s time.” Yes, the last instance was 1865, when John Wilkes Booth murdered Abraham Lincoln, a president who even modern liberals claim to respect. Depp later apologized, claiming he “was only trying to amuse.”

Obviously, being an actor doesn’t make one a comedian. And even professional comedians sometimes fail to make people laugh. When Kathy Griffin’s stunt with a bloody, decapitated head of President Trump blew up, she claimed victimhood because people didn’t get the “joke.”

At least these two were one-off “performances.” New York City Public Theater’s Shakespeare in the Park production of Julius Caesar features the title character being knifed with great enthusiasm midway through the play. This “Roman” sports a suit, unruly blonde hair, and red tie, and has a spouse with a Slovenian accent. Wonder who that’s supposed to be?

The real Caesar was a general who used military success to destroy a republic and become a dictator. It’s a great story, and in 1937 the celebrated Orson Welles used the play to target Italy’s Benito Mussolini, who was a fascist dictator and later allied himself with Adolf Hitler in World War II.

But President Trump, freely elected by the American people and acting within the U.S. Constitution, being portrayed as Caesar? And deserving to be assassinated? Really?

Of course, no one involved in these incidents said they supported harming the president. But a couple weeks back a Nebraska Democratic Party official said he was “glad” that House Majority Whip Steve Scalise was shot. Not just that, but “I wish he was [expletive] dead.”

Phil Montag did this in a conversation with Chelsey Gentry-Tipton, chairwoman of the state party’s Black Caucus, who previously remarked that it was “so funny” to watch GOP legislators “crying on live TV” about the horror of the attack. She added: “Yeah, having a hard time feeling bad for them.”

And liberals accuse President Trump of degrading America’s political discourse?

Americans always have engaged in vigorous debate. They should continue doing so. But vigorous doesn’t mean vicious and malevolent. It’s time for decent liberals to hold their less principled colleagues to account.