Third, a Warren presidency would be deeply polarizing and probably unsuccessful. Warren’s policy ideas would make any progressive-moderate coalition impossible. She’d try to govern with her 40 percent partisan base, just as Trump has, which is no way to pass big legislation.

Fourth, there is a wave of insular intolerance coursing through parts of the American left. If given executive power, some progressives may use it to cancel any culture or faith other than their own.

And yet ….

And yet, if it comes to Trump vs. Warren in a general election, the only plausible choice is to support Warren. Over the past month Donald Trump has given us fresh reminders of the unique and exceptional ways he corrupts American life. You’re either part of removing that corruption or you are not. When your nation’s political system is in danger, staying home and not voting is not a responsible option.

Politics is downstream from morality and culture. Warren represents a policy wrong turn, in my view, but policies can be argued about and reversed. Trump represents a much more important and fundamental threat — to the norms, values, standards and soul of this country.

Last week, Trump all but greenlighted the ethnic cleansing of Kurds without an ounce of remorse. He normalizes dishonesty and valorizes cruelty. His letter to President Recep Tayyip Erdogan reminds us yet again that we have a president whose professional competence is at kindergarten level. Once a nation has lost its heart, mind and soul, it is very hard to get these things back.

Furthermore, Trump is an unprecedented threat to democratic institutions. Over the past few years, I’ve thought the progressive fears of incipient American fascism were vastly overblown. But, especially over the past month, Trump has worked overtime to validate those fears and to raise the horrifying specter of what he’ll be like if he is given a second term and is vindicated , unhinged and unwell.

In their book “How Democracies Die,” Steven Levitsky and Daniel Ziblatt argue that authoritarians undermine democracy in several ways. They reject the democratic rules of the game, the unwritten norms we rely upon to make the political system work. They deny the legitimacy of their political opponents, using extreme language to deny them standing as co-citizens. They tolerate or even encourage violence, threatening to take legal action against critics in rival parties.