Donald Trump’s broadsides against the “dishonest” media rank among his most reliable applause lines — right up there with "build the wall." But there is one big exception: his mockery of a New York Times reporter who has a physical disability.

Nine months after a rally in South Carolina where Trump contorted his arms in a way that was clearly meant to imitate the effects of arthrogryposis, which visibly limits flexibility in the arms of journalist Serge F. Kovaleski, voters say the incident still disturbs them. In a Bloomberg Politics poll published Thursday, 83 percent of respondents said they are bothered by the episode — more than said they were bothered by Trump’s recent feud with a Gold Star family, his praise for Russian President Vladimir Putin or lawsuits against Trump University.

In fact, making fun of a reporter with a disability registered as more unsettling than any concern about either major-party presidential nominee in the survey — ahead of Hillary Clinton's email scandal, even.

Democrats have known for a while that Trump’s attack on Kovaleski had a powerful effect on voters. Before the first ballots of the primary season were cast, a pro-Clinton super PAC was already using it in a well-funded ad campaign.

The Associated Press reported in January that Priorities USA found “the footage of him appearing to mock a disabled reporter stands out, evoking one of the strongest reactions from voters in focus groups and other forums.”

More recently, the Clinton campaign has used the clip of Trump feigning spasms in its own commercial.

Ordinarily, reporters are not sympathetic targets. Only 40 percent of Americans trust the mass media, according to Gallup. When Sen. Ted Cruz (R-Tex.) ripped the media during a GOP debate last fall, Republican pollster Frank Luntz reported the most favorable reaction in a focus group that he had ever seen.

People clearly love to see the press take a beating, yet they are also clearly uncomfortable with watching anyone — even someone in an unpopular profession — endure ridicule for a disability.

For the vast majority of Americans, that is a line you just don’t cross. But Trump crossed it, and people have not forgotten.