By Albert Hunt

Bloomberg View

The Trumpist right, with its conspiracy theories, racist demagoguery and blatant lies, should embarrass honest conservatives and responsible Republicans. There also is a loony left, which though less pervasive and powerful, needs to be condemned by liberals.

Its theories excuse efforts to suppress speech by conservatives, especially on college campuses. Its attacks on Trump go well beyond acceptable criticism — think of comedian Kathy Griffin’s video with a severed Trump head. Its activists, who include some elected officials, call for impeachment of the president before taking the trouble to build a constitutionally persuasive case.

Consider Tim Canova, a law professor at Nova University in Florida, who is waging a Democratic Party primary battle against Rep. Debbie Wasserman Schultz. He has suggested that a young Democratic staffer may have been murdered last year because the staffer, not Russian hackers, leaked the damaging information from the party’s national committee that sabotaged Hillary Clinton’s presidential campaign. He’s downplayed the conclusion of U.S. intelligence agencies that Russia meddled in the presidential election, and questions whether he is being hacked by political opponents.

Canova was embraced last year by Vermont Sen. Bernie Sanders out of resentment against Wasserman Schultz who, as Democratic chair in 2016, sought to tilt the party machinery in favor of Clinton. Canova ran a strong race, raising tons of money, but lost. Sanders seems to be staying away from the current challenge.

In the Atlantic last week, McKay Coppins reported on leftist conspiracy theorists like the Palmer Report, a blog that focuses on Russia. It reported in April that Rep. Jason Chaffetz, R-Utah, was resigning because of Russian blackmail. The whole story was nonsense.

Sites like this, Coppins wrote, embrace a world “where it is acceptable to allege that hundreds of American politicians, journalists and government officials are actually secret Russian agents.”

Someone check Sen. Joseph McCarthy’s gravesite.

The far left is divided on Russia and its thuggish leader Vladimir Putin. Many progressives are harshly critical, driven by their hostility to Trump and eager to believe that there are Trump ties to Putin.

But there is another element too. At the Moscow feast in December 2015, where Trump’s foreign policy adviser Michael Flynn sat next to Putin, another Western politician at the head table was Jill Stein, the two-time Green Party presidential candidate. (She said she didn’t even say hello to the Russian leader.)

Canova’s most offensive gambit has been recycling a baseless right-wing conspiracy theory that a young Democratic staffer, Seth Rich, was murdered last year because he leaked the party emails in the presidential election. This was a charge leveled by Alex Jones, the conspiracy-minded talk-radio host, and picked up by former House Speaker and present Trump confidant Newt Gingrich. The police found that Rich was murdered after a botched robbery attempt. Fox News retracted its own twisted story on the Rich killing.

Not Canova. Asked by the Florida Sun Sentinel and Miami Herald whether Rich’s murder may have been related to the leaks, Canova replied: “I have no idea. I wondered what the DNC under Wasserman Schultz was capable of, but I don’t know.”

Calls to the number listed on his campaign website and messages to the designated email site went unanswered.

If this were a unique case, it would be enough to criticize Canova and move on. But anti-Trump passion will tempt liberals to make excuses for radical craziness, just as many mainstream Republicans have tolerated Trump’s lies, insults and attacks. To keep the high ground, liberals should resist the urge to whip up hostility, and should condemn hate-mongers of the left.

Albert Hunt is the executive editor of Bloomberg News.