With many big-name conservative commentators vigorously opposed to — or, at least, highly skeptical of — Donald Trump, cable news channels have looked to the end of the bench for articulate, telegenic supporters of the Republican presidential front-runner.

Who outside Boston had heard of Adriana Cohen before she accused Ted Cruz's former communications director, live on CNN last month, of sleeping with the Texas senator? And who, since season one of "The Apprentice," had cared what Omarosa Manigault said, until she made an off-the-wall remark about Fox News Channel contributor Tamara Holder's "big boobs" during an interview on Fox Business Network in February?

In other words: A good Trump surrogate — or at least one who won't send a TV segment careening off the rails — can be hard to find. Media outlets aren't really in a position to scratch names off an already-short list.

So it's pretty remarkable that two of the three major cable news channels have blacklisted Roger Stone, the veteran Republican strategist who is one of Trump's most vocal allies and who had been a regular television presence.

CNN banned Stone in February, after he tweeted sexist, racist comments about two of the network's on-air personalities. On Monday, MSNBC edited out a Stone interview that was part of that day's episode of "With All Due Respect," a weekday program that airs earlier on Bloomberg TV. The Stone interview was included in Bloomberg's broadcast but cut from MSNBC's. The liberal press watchdog group Media Matters was first to flag the edit.

An MSNBC spokesman said in an email to The Fix that "Roger Stone will not be a guest on MSNBC because of his now very well-known offensive comments."

Fox News Channel has not banned Stone, according to a spokeswoman; he was a guest on "Mornings with Maria" on Fox Business Network on Monday. The Washington Post also does not have a policy against quoting Stone.

Stone, once an aide to Richard Nixon, has not responded to a request for comment.

But being placed on TV networks' no-fly lists surely pains the 64-year-old, who sports a nuclear-blond hairdo that rivals his favorite candidate's. Quoting Gore Vidal, Stone told the New York Times last August that his philosophy is to "never miss the opportunity to have sex or be on television."


Roger Stonce, center, pictured in 1985 with fellow Republican operatives Paul Manafort, left, and Lee Atwater. (Photo By Harry Naltchayan/The Washington Post).

Stone spoke to the Times shortly after splitting with Trump, to whom he had been an adviser. He said he quit; Trump said he was fired. The two have an on-again-off-again relationship.

Stone advised Trump when he mulled a presidential bid in 2000. In 2008, the real estate mogul told the New Yorker that "Roger is a stone-cold loser." (Get it?)

The latest breakup appears to have been more amicable, however. Though he no longer represents Trump in an official capacity, Stone remains an active evangelist for the billionaire White House hopeful. On Wednesday, he appeared on the "Alex Jones Radio Show" (speaking of the end of the bench) to tell the host — a 9/11 conspiracy theorist — about his plan to "man the ramparts" at a hypothetical contested Republican convention.

"We will have demonstrations at specific hotels where there are delegates so we can let them visually see the will of the people," Stone said. "We will have a daily protest. We will man the ramparts every day."

He said earlier in the week in an interview on Freedomain Radio, a libertarian podcast, that if delegates were to nominate a candidate other than Trump, he would "disclose the hotels and the room numbers of those delegates who are directly involved in the steal" — an alarming proposition, given that Trump has said he thinks "you'd have riots" if another candidate were to emerge from a contested convention. Stone insisted to Jones that "we're not talking about roughing anybody up."

When the National Enquirer published unsupported rumors of serial infidelity by Cruz on March 23, it quoted Stone, who claimed that "these stories have been swirling around Cruz for some time. I believe where there is smoke, there is fire." Stone denied in a subsequent interview with a New York radio station that he planted the story.

In a 1986 profile of Stone, The Washington Post's Stephanie Mansfield described him as a "college dropout and Watergate dirty trickster." She chronicled some of his earliest campaign shenanigans.

In the fall of 1970, Stone moved to Washington to attend George Washington University. He became president of the District of Columbia Young Republicans. While his roommates were protesting the Vietnam War, Stone says, he was attending meetings of the Young Americans for Freedom. He also volunteered to work for Chuck Colson at the Committee to Re-Elect the President (CREEP). He became an assistant to Bart Porter, who helped manage the dirty tricks operations. Under the pseudonym "Jason Rainier," Stone went to Kentucky and recruited a political spy, paying him $5,800 for information on Democratic opponents. He also went to New Hampshire and donated money to the abortive presidential campaign of Rep. Pete McCloskey (R-Calif.) in the name of a left-wing group called the Young Socialist Alliance. Stone then drafted a letter to the Manchester (N.H.) Union Leader describing the contribution, enclosing a receipt from the McCloskey campaign.

"They were all dumb ideas," he says now. "I did some things, in retrospect, which were in terribly poor judgment. I was caught up in the hysteria of the times."

The 2008 New Yorker piece, another profile of Stone, was headlined "The Dirty Trickster" and characterized him as "a political consultant and lobbyist who, in conventional terms, was highly successful, working for such politicians as Bob Dole and Tom Kean. Even then, though, Stone regularly crossed the line between respectability and ignominy, and he has become better known for leading a colorful personal life than for landing big-time clients."

Writer Jeffrey Toobin wrote that he interviewed Stone at "the leading 'swingers' club' in Miami, and Roger Stone took me there to explain the role he may have played in the fall of Eliot Spitzer, the former governor of New York."

Stone seems to relish controversy and notoriety. His personal website features a photograph of him and Nixon, smiling side by side, near the top of the homepage. More permanently, he has Nixon's mug tattooed on his upper back. In other words, he's not exactly running from the "dirty trickster" moniker.

Now two cable news channels have decided to run him off their air. The search for Trump backers who are suitable for television continues.