For people who so often accuse Hillary Clinton of lying, the Republican presidential candidates seem to feel perfectly free to bend, twist, and shred the truth at will. Unsurprisingly, that is just what several of them were caught doing in their free-for-all CNBC debate. They prevaricated about themselves, their policies, and their opponents, without blinking an eye – and for the most part, they got away with it.

Do nice people tell self-serving lies? Perhaps they do, because it was terribly nice Ben Carson who uttered one of the most blatant whoppers of the evening.

To loud booing from the partisan audience, moderator Carl Quintanilla asked the soft-spoken neurosurgeon about his long and lucrative involvement with Mannatech, a nutritional supplement manufacturer that has been cited for false health claims for its “glyconutrients.” (How bad was Mannatech? Bad enough to provoke a fraud action brought by Greg Abbott, the former Texas attorney general who is now that state’s very conservative governor.)

“I didn’t have an involvement with [Mannatech],” retorted Carson. “That is total propaganda, and this is what happens in our society. Total propaganda.”

What Carson’s noisy fans probably didn’t know is that this was no “liberal media” setup. The doctor’s decade-long relationship with Mannatech – which turns out to have included a written contract, paid speeches, and a video endorsement on the company’s website – was exposed last year by Jim Geraghty of National Review, the flagship publication of American conservatism. Following the debate, Geraghty slammed Carson for “bald-faced lies” and “blatantly lying” about his relationship with the supplement firm.

Equally mendacious about his own personal history was Marco Rubio, who “won” the debate according to many observers. When Becky Quick of CNBC asked a predictable question about his checked financial affairs, which have included foreclosures, liquidations, phony expense accounts, and other embarrassments, the senator from Florida shot back: “You just listed a litany of discredited attacks from Democrats and my political opponents, and I’m not gonna waste 60 seconds detailing them all.”

Discredited attacks? Actually, Quick’s question was premised on facts that are not in dispute – as even Rubio himself acknowledged in his own campaign book. So frontally deceptive was his response that an outraged Joe Scarborough, his fellow Florida Republican, called him out on MSNBC’s Morning Joe the next day.

“Marco just flat-out lied to the American people there,” Scarborough complained. “And I was stunned that the moderators didn’t stop there and go, ‘Wait a second, these are court records. What are you talking about?…Becky was telling the truth, Marco was lying. And yet everybody’s going, ‘Oh, Marco was great.’ No, Marco lied about his financials.” Not incidentally, Rubio also lied about the effects of his tax plan, claiming his tax cuts would mostly benefit lower-income families when in fact its biggest benefits would accrue to the top one percent, as Republican tax schemes almost always do.

Another brand of lie was pronounced by Carly Fiorina, who drew attention at the last GOP debate by insisting she had watched a grisly Planned Parenthood video that doesn’t exist. This time, she reached back to the 2012 Republican campaign to invent a factoid about women’s employment.

Fiorina tries to sell herself as the candidate tough enough to take down Clinton, and tries to prove it by making stuff up. At this debate, she huffed:

It is the height of hypocrisy for Mrs. Clinton to talk about being the first woman president, when every single policy she espouses and every single policy of President Obama has been demonstratively bad for women. Ninety-two percent of the jobs lost during Barack Obama’s first term belonged to women.

But as PolitiFact quickly established, that statement was false in every particular. Not only did women not lose “92 percent” of the jobs in Obama’s first term, the number of women employed during the period from January 2009 to January 2013 grew by 416,000. Naturally, as she did with Planned Parenthood, Fiorina angrily repeated the lie when challenged.

Fiorina isn’t the only Republican who doesn’t like being exposed. Rubio ridiculously claimed that the “mainstream media” is really a Democratic SuperPAC. And now RNC chair Reince Priebus has reneged on the party’s debate agreement with NBC News. He and his candidates just couldn’t handle two hours of sharp but thoroughly polite questioning.

They constantly insult Clinton, but how would any of these slippery blowhards survive something like the 11-hour Benghazi grilling she breezed through on Capitol Hill? If you want to understand who they are, just listen to them whine.

Photo: Republican U.S. presidential candidates (L-R) former Governor Jeb Bush, U.S. Senator Marco Rubio, businessman Donald Trump, Dr. Ben Carson, former HP CEO Carly Fiorina and U.S. Senator Ted Cruz, pose before the start of  the 2016 U.S. Republican presidential candidates debate held by CNBC in Boulder, Colorado, October 28, 2015. REUTERS/Rick Wilking