There are lots of issues to discuss regarding last night’s second presidential debate in St. Louis.
We could talk about the fact that Hillary Clinton was at the top of her game, delivering a solid debate performance, even as her opponent waded deeply into the political sewer.
We could talk about the fact that Donald Trump publicly upbraided his running mate Mike Pence on a question about Syria in order to take the side of Vladimir Putin (and Syrian strongman/butcher Bashar al-Assad).
We could talk about the fact that Trump said Captain Humayun Khan would be alive if Trump had been president — as he once again lied about his support for the war in Iraq.
We could talk about the fact that almost every word out of his mouth was untrue; that he dredged up every right-wing conspiracy theory that finds home in the conservative fever swamp; and that he had three women who have accused Bill Clinton of sexual impropriety as guests at the debate.
Finally, we could talk about how this debate — solely because of the presence of Donald Trump — was an appalling spectacle that degraded and debased our democratic system.
All of that is secondary to the fact that Donald Trump said Hillary Clinton would be in jail if he were president.
It’s secondary to the fact Trump said that if he became president he would “instruct my attorney general to get a special prosecutor to look into your situation, because there’s never been so many lies, so much deception.”
When you are threatening to investigate and then jail your political opponent in a presidential debate you have crossed an exceptionally dangerous line.
This is Trump saying that the director of the FBI and the US attorney general are corrupt because they cleared Clinton of any wrongdoing in the investigation of her emails. This is Trump saying that he will order his attorney general and the Department of Justice to investigate and jail the runner-up in the presidential election. This is Trump suggesting that if he becomes president he would simply throw people in prison, because he “alone” determines that they are guilty of a crime. This is an abrogation of the rule of law in America and a fundamental violation of the democratic norms that allow for the peaceful turnover of power from one political party to the other.
And you know the absolute worst part about this? When Trump said it, his partisans in the crowd cheered. This is banana republic territory. This is what fascism in America looks like.
Ignore everything else that happened Sunday night. Ignore the lies; the exaggerations; the grossness of Trump calling bragging about sexual assault “locker room talk.” This is the headline.
Yet, what is perhaps more remarkable is that this was not the only thing we were talking about after the debate. The initial talking head reaction to the Clinton-Trump showdown practically ignored Trump’s comments or treated it as just another talking point in the debate. Some of Trump’s enablers/surrogates said he was joking — as if throwing a political rival in jail could ever be considered humorous.
This is precisely how undemocratic behavior gets normalized: by a pliant news corps that doesn’t understand a threat to democracy when they see it and that treats political debates like they are nothing more than electoral theater.
Frankly, I don’t care if Trump’s debate performance played badly with suburban female voters. I don’t care if Clinton seemed defensive and Trump was aggressive. I don’t care if Trump quieted the calls from Republican politicians to step down from the ticket.
What I do care about — and frankly what all of us should care about — are the implications of a presidential candidate openly, in a presidential debate, threatening to investigate and imprison his opponent.
Donald Trump is a clear and present danger to our democracy. He’s a man with a dangerously authoritarian mindset. He’s a man with no respect for and no knowledge of the basic political norms and values that guide our 240-year experiment in democracy.
There’s nothing else for us to discuss after Sunday night’s debate.
Michael A. Cohen’s column appears regularly in the Globe. Follow him on Twitter @speechboy71.