You’ve probably already seen the tweet that Howard Dean posted last night:

Notice Trump sniffing all the time. Coke user? — Howard Dean (@GovHowardDean) September 27, 2016

That seems pretty out there for someone who is a medical doctor. But Dean refused to back down Tuesday, telling MSNBC that he wasn’t making a diagnosis via television and then going on to suggest Trump might have a cocaine habit.

“You can’t make a diagnosis over the television. I would never do that but he has some interesting…that is actually a signature of people who use cocaine,” Dean said. He continued, “I’m not suggesting that Trump does but…” At this point he was cut off by host Kate Snow who interjected, “Well, you are suggesting it actually in a tweet.” Dean replied, “No, I’m suggesting we think about it because here’s the interesting constellation.

“So, he sniffs during the presentation which is something that users do. He also has grandiosity which is something that accompanies that problem. He has delusions—I’m not talking about being crazy, but for example when he told everybody it was smart not to pay taxes and then denied he said it after he said it in front of 100 million people. It’s not that he’s delusiairy [A real word?] about it it’s that he thinks somehow that he won’t get caught. That is delusional. He has trouble with pressured speech. He interrupted, as you pointed out, Hillary Clinton 29 times. He couldn’t keep himself together. So, look, do I think at 70 years old he has a cocaine habit? Probably not. But (laughs) you know, it’s something I think it would be interesting to ask him and see if he ever had a problem with that.”

MSNBC host Kate Snow seemed pretty astounded by this. “So as a physician and as a medical person yourself, you’re suggesting that we ought to look at whether the Republican candidate for President has a cocaine habit,” she said. Dean then claimed once again he wasn’t making a diagnosis but then repeated that “these four symptoms” were “striking.”

When Snow compared what Dean was doing to comments Rudy Giuliani had made about Hillary Clinton’s health, Dean suggested Trump needed to release his medical records and tax returns.

A few points about all of this. First, Howard Dean endorsed Clinton and spoke at the Democratic convention this summer. He’s firmly on team Clinton. In fact, this is not even the first time he has used his medical opinion in this campaign. When Clinton collapsed earlier this month, Dean tweeted that it was not a big deal “from a medical point of view.”

From a medical point of view this is not a big deal, She needs to cancel some events or do them by Skype for a week. https://t.co/S6BV5vh1K5 — Howard Dean (@GovHowardDean) September 12, 2016

Second, Dean isn’t doing this off the cuff. He came with prepared talking points to suggest Trump might be a coke-head. Also the line about running a presidential campaign at 70 is one he repeats a couple of times almost verbatim. This attack was prepared in advance.

Third, even if you assume the Clinton camp was taken by surprise by Dean’s tweet last night, one call could have shut down this MSNBC interview before it happened. So it’s fair to assume that, at least tacitly, the campaign doesn’t have a problem with Dean doubling down on this.

Keep in mind, one of Hillary’s big moments in last night’s debate was hitting Trump over his birtherism attack on Obama while also maintaining she had nothing to do with it. And yet, only a few hours later one of her supporters is on television launching an incredibly sleazy attack on her opponent and she’s what…not aware of it this time either? Will anyone ask the campaign to denounce Dean for this?

The Clintons love to play the martyr in the media, but they fight as dirty as anyone in politics. When Trump goes low, Hillary goes lower.