The television networks that promoted Trump; the primary voters who elevated him; the politicians who eventually surrendered to him; the intellectuals who argued for him, and the donors who, however grudgingly, wrote checks to him—all of them knew, by the time they made their decisions, that Trump lied all the time, about everything. They knew that Trump was ignorant, and coarse, and boastful, and cruel. They knew he habitually sympathized with dictators and kleptocrats—and that his instinct when confronted with criticism of himself was to attack, vilify, and suppress. They knew his disrespect for women, the disabled, and ethnic and religious minorities. They knew that he wished to unravel NATO and other U.S.-led alliances, and that he speculated aloud about partial default on American financial obligations. None of that dissuaded or deterred them.

And the “them” is growing. When I wrote about the Trump candidacy last fall, that candidacy was still backed only by one-third of Republicans, most typically the party’s least-affluent, least-educated, and least-churched supporters. Back then, I offered four guesses about the party’s response to Trump: beat him, steal his issues, ignore him, or change the rules to circumvent him. I under-estimated him—or possibly over-estimated his party. Trump steadily added to his support, moving up-market and up in the polls. In the Oregon Republican primary of May 17, the first after his last rivals conceded defeat, Trump won 66.6 percent of all votes cast. Polls in late May show 85 percent of Republicans now supporting Trump.

Those of us who live and socialize among conservatives every day discover that another friend has—with greater or lesser reluctance—accepted the leadership of the bombastic businessman and reality-television star. To those of us who still cannot imagine Trump as either a nominee or a president, this movement toward him among our friends, relatives, and colleagues is in varying degrees baffling and sinister. Yet it is happening: an inescapable and accelerating fact.

Whatever the outcome in November, conservatives and Republicans will have brought a catastrophe upon themselves, in violation of their own stated principles and best judgment. It’s often said that a good con is based upon the victim’s weaknesses. Why were fconservatives and Republicans so vulnerable? Are these vulnerabilities not specific to one side of the political spectrum—are they more broadly present in American culture? Could it befall liberals and Democrats next time? Where were the guardrails?

Let’s survey the breakage, from earliest to latest, and from least to most alarming.

The first guardrail to go missing was the old set of expectations about how a candidate for president of the United States should speak and act. Here’s Adlai Stevenson accepting the Democratic nomination for president in 1952:

That I have not sought this nomination, that I could not seek it in good conscience, that I would not seek it in honest self-appraisal, is not to say that I value it the less.

There was a certain quantum of malarkey here—but it wasn’t all malarkey. From the founding of the republic, Americans have looked to qualities of personal restraint as one of the first checks on the power of office. "The aim of every political Constitution is or ought to be first to obtain for rulers, men who possess most wisdom to discern, and most virtue to pursue the common good of the society; and in the next place, to take the most effectual precautions for keeping them virtuous, whilst they continue to hold their public trust.” So argued James Madison in Federalist 57. In Federalist 68, Alexander Hamilton promised more specifically: “Talents for low intrigue, and the little arts of popularity, may alone suffice to elevate a man to the first honors in a single State; but it will require other talents, and a different kind of merit, to establish him in the esteem and confidence of the whole Union, or of so considerable a portion of it as would be necessary to make him a successful candidate for the distinguished office of President of the United States.”