Just over three years after Donald Trump announced his candidacy for president claiming that Mexican immigrants are rapists and criminals, and then proceeded to cut a swath of resentment, anger and hate across America, we've all become terribly concerned that a Democrat here or there has been uncivil to the people who work for this least civil of presidents. I can almost hear the cackles of glee from the White House.

It's as though I stood outside your door for years, blasting death metal through gigantic speakers, then when you finally shouted, "Hey, keep it down!" I demanded that the police arrest you for disturbing the peace.

Have we gone nuts?

If you're a Democrat in Washington, there are some double standards you've gotten used to, exasperating as they may be. For instance, any Democratic policy idea is immediately answered with "But how are you going to pay for it?" with endless stern lectures about the deficit we're leaving our grandchildren. Then Democrats watch as Republicans balloon the deficit with tax cuts and still pose as advocates of "fiscal conservatism."

But to hear, in the era of Trump, that liberals are the ones being "uncivil"? You have to be kidding me.

What are the horrors to which Trump and his aides have been subjected? White House press secretary Sarah Huckabee Sanders was politely asked to leave a restaurant after staff members expressed their concerns about Trump administration policies to the owner (and they comped her cheese plate).

Secretary of Homeland Security Kirstjen Nielsen was heckled at a Mexican restaurant by protesters angry about the administration's policy of separating parents and children at the border.

And Rep. Maxine Waters, D-Calif., a regular Trump antagonist, told a group of supporters, "If you see anybody from that Cabinet in a restaurant, in a department store, at a gasoline station, you get out and you create a crowd. And you push back on them. And you tell them they're not welcome anymore, anywhere."

Oh, and Robert De Niro said the f-word at the Tony Awards.

Now let's take a moment to remember who it is these dreadfully uncivil Democrats are opposing. Trump transformed himself into a political figure by leading a racist crusade charging that President Barack Obama was not born in the United States. Trump mocked a disabled reporter. He encouraged his supporters to commit acts of violence when protesters arrived at his rallies ("I'd like to punch him in the face, I tell ya."). He retweeted racist memes. He made up belittling nicknames for all his opponents.

Trump signaled his supporters that they no longer had to be "politically correct" or treat people they didn't like with any respect.

But it's more than just him.

In 1988, the young Republican Congressman Newt Gingrich shocked his colleagues by telling them that the disagreements they had with liberals over policy were nothing short of war.

"This war has to be fought with a scale and a duration and a savagery that is only true of civil wars," he said. He spread a gospel of total opposition and vilification, in which Democrats had to be not just opposed but destroyed — politically, personally, in every way possible. And while older politicos thought that went too far, an entire generation of Republican politicians and activists came of age listening to tapes and reading material created by GOPAC, a group affiliated with Gingrich, telling them how to treat their opponents. In one famous document, titled "Language: A Key Mechanism of Control," they were advised that when talking about Democrats, they should use words like "decay," "sick," "betray," "pathetic," and "traitors."

In dragging politics down to his level, Gingrich was extraordinarily successful. Fast-forward to the Obama years, when Republicans no longer considered it necessary to treat the president with any respect. They spread conspiracy theories, they claimed he was intentionally trying to destroy the country. One even shouted, "You lie!" at the president during an address to a joint session of Congress.

And now, after they lined up in support behind a walking collection of character flaws who rode to the White House on a campaign of hate and fear, Republicans pretend to be offended when liberals can no longer contain their anger?

Liberals are getting a little tired of being civil. For decades, they've been told that they had to be better, more serious, substantive, ethical and polite; while we just shouldn't expect anything similar from Republicans. Can you blame them if they've had just about enough?

Paul Waldman is an opinion writer for the Plum Line blog.