Republican presidential candidates frequently complain about reporters, but they routinely face even greater ridicule by a wing of the media that makes no pretense to being fair and balanced — television’s late-night humorists. Front-runner Donald Trump was recently the target of a harsh, unprecedented 22-minute monologue by HBO’s John Oliver, who uncovered Trump’s ancestral name and urged viewers to “Make Donald Drumpf Again.” The segment has been viewed about 20 million times on YouTube.

Candidates frequently try to neutralize the mocking by appearing on these late-night entertainment shows to demonstrate to viewers that they can take a joke and even be in on one. But it doesn’t always work for Republicans, such as when Ted Cruz endured a hostile interview and audience booing on “The Late Show with Stephen Colbert.” Even the blustery, confident Trump was unusually circumspect when he appeared face to face with Colbert, who has joked that Trump does poorly with evangelical Christian voters because he looks too much like a golden calf.

But for all the hubbub and breathless news coverage that attend presidential aspirants’ occasional appearances on these shows, the real story is the steady stream of derision that permeates the nightly monologues and skits of the hosts. And Republicans have long viewed this material as Democratic-leaning propaganda. Four years ago, Mitt Romney resisted going on late-night talk shows, fearing that he would be dealing with hostile interviewers. He eventually appeared on “The Tonight Show,” based on conservatives' beliefs that host Jay Leno was more receptive to guests on their side of the aisle.

In the 2016 primary season, our research supports Romney’s reservations. We are tracking political jokes by Jimmy Fallon, Stephen Colbert, Jimmy Kimmel and new "Daily Show" host Trevor Noah (whose liberal bent is much more apparent). For the five months from last September through January, Republican presidential candidates were the targets of more than three times as many jokes as their Democratic counterparts — 1,363 vs. 424 jokes overall.

Trump, the blustery businessman who by himself was the subject of 655 of those jokes, is clearly a target-rich environment for humorists. But he is not the whole story here. Jokes about all the other Republican candidates still outpaced all the Democratic candidates combined, even without Trump, by nearly 300 quips.

In contrast, Democratic front-runner Hillary Clinton inspired only 216 jokes, barely outpacing the hapless Jeb Bush, whose sputtering campaign attracted 193 punchlines. Further back in the field was the Democratic contender Bernie Sanders, at 164 jokes.

Saying little on the campaign trail does not spare a candidate from the comedic attacks. Consider a recent “Tonight Show” jab at Ben Carson, who was the subject of 157 jokes. “Ben Carson's the first human to get 25 hours of sleep per day. I feel bad making fun of Carson, but it's not like he's gonna see it,” Fallon said following one of Carson’s understated debate performances.

Even after expanding our study to include all political figures, including President Obama, Vice President Biden and former president Bill Clinton, Republicans still attracted more than 70 percent of the jokes over the past several months. Moreover, previous research shows that Republican presidential nominees have attracted more jokes than their Democratic counterparts in every general election since 1992.

So this cycle’s late-night tilt so far fits a longtime pattern, which may reflect the liberal cast of the entertainment industry. For example, a 2012 Pew Research Center study found that the audience for “The Daily Show” and Colbert's old show, "The Colbert Report," skewed farther left than any major news source, except for MSNBC’s “Rachel Maddow Show."

For whatever reason, on the road to the White House, the late-night jeers veer sharply to the right.

If Donald Trump is the GOP nominee, he may prove as impervious to the zingers of comedians as he is to the put-downs of media commentators and to the debate attacks of his fellow Republican presidential candidates. If Trump survives this year’s withering comedic assault, he would be the exception to patterns seen in previous election cycles. In general, research shows that the higher the late-night joke totals, the lower a candidate’s popularity with voters. Considering the dismal favorability ratings of their leading candidates this year, the humor gap is no laughing matter for Republicans.

Robert Lichter is professor of communication at George Mason University and co-author of “Politics is a Joke: How TV Comedians are Remaking Political Life.” Stephen J. Farnsworth is professor of political science at the University of Mary Washington and author of “Spinner in Chief: How Presidents Sell Their Policies and Themselves.” Deanne Camieso is a graduate student in communication at George Mason University.