Last week, the Cruz campaign took a hit when it was revealed that someone in the campaign approved a deceptive mailing campaign, designed to prod Iowa voters into caucusing by claiming that those who stayed home in past caucuses had committed a “Voting Violation”— two words which the mailer featured in bright red ink. That tactic was so heavy-handed that it seemed implausible a savvy politician such as Cruz had himself approved it, but the mailer definitely originated with someone in Cruz’s operation, as the campaign admitted. No one has yet been fired for greenlighting it.

Now there’s a charge of another violation of whatever “gentleman’s code” still prevails in a race as crucial as Iowa’s. According to Fox News:

Republican presidential hopeful Ben Carson on Tuesday pointedly accused Ted Cruz’s campaign of spreading false rumors during the Iowa caucuses claiming the retired neurosurgeon was suspending his bid, in a coordinated effort to seal Cruz’s victory Monday night.

The stunning charge came as a Carson spokesman declared, “There has never been a more tainted victory in the Iowa caucuses.”

Carson’s spokesman probably had forgotten the last GOP Iowa caucuses, when the long-shot Rick Santorum actually collected the most votes, but counting “irregularities” gave an apparent victory to the well-oiled machine that was the Mitt Romney campaign — with the real vote only coming out months later, when it was too late to do Santorum any good.

Fox explained how the Carson rumor played out:

Upon hearing reports that their candidate was leaving the trail to return to his home in Florida, Team Carson responded swiftly, saying the retired neurosurgeon was only going home for clean clothes but was then headed to New Hampshire for the Feb. 9 primary.”

But Carson told Fox News Tuesday morning that Cruz supporters and representatives took that narrative a step further, and began telling caucus-goers at “many” precincts that he was dropping out.

The Hill reported that Cruz has acknowledged the campaign tactic, and apologized, attributing it to a misreading of the news:

“Last night when our political team saw the CNN post saying that Dr. Carson was not carrying on to New Hampshire and South Carolina, our campaign updated grassroots leaders just as we would with any breaking news story,” Cruz said in a statement.

“That’s fair game. What the team then should have done was send around the follow-up statement from the Carson campaign clarifying that he was indeed staying in the race when that came out.

“This was a mistake from our end, and for that I apologize to Dr. Carson.”

CNN broadcast Cruz’s apology, with commentary:

Carson is not satisfied with this explanation, according to Fox, which reported: “Carson said if Cruz was unaware of the tactics, then he should find out who was involved and fire them. And if Cruz knew about the effort, he should admit his involvement and ‘offer a solution,’ Carson said.

Given that Cruz is competing with Carson for evangelical voters, the perception that Cruz’s campaign is behaving in a Machiavellian fashion could be particularly damaging. On the other hand, it might prove awkward to fire staffers right after a decisive and unexpected victory, such as Cruz’s team saw in Iowa. It remains to be seen if the elements in Cruz’s campaign which regard such tactics as legitimate will be reined in, after so much public blowback.