Meanwhile, on the Democrats’ side:

— They are running a presidential campaign decrying wage stagnation, income inequality and widespread economic malaise — as if they’ve not been in office for the past seven years.

— Their leading presidential candidate is 27 points underwater on the question of honesty and is under FBI investigation for possible mishandling of classified information.

— Her chief challenger is a 74-year-old socialist with a near-spotless record of invisibility in 25 years in Congress. The other three candidates can hardly be found at all.

— The only plausible alternative challenger, Joe Biden, has run and failed twice and, before tragedy struck (to which he has responded, one must say, with admirable restraint and courage), was for years a running national joke for his endless gaucheries and verbal pratfalls.

For the GOP, this has all been a godsend, an opportunity to amplify the case being made every day by the Democrats themselves against their own stewardship. Instead, the Republicans spent the summer attacking each other — the festival of ad hominems interrupted only by spectacular attempts to alienate major parts of the citizenry.

The latest example is Ben Carson, the mild-mannered, highly personable neurosurgeon and one of two highest-polling GOP candidates. He said on Sunday that a Muslim should not be president of the United States.

His reason is that Islam is incompatible with the Constitution. On the contrary. Carson is incompatible with a Constitution that explicitly commands that “no religious test shall ever be required as a qualification to any office or public trust under the United States.”

Ever. And it is no defense of Carson to say that he was not calling for legal disqualification of Muslims, just advocating that one should not vote for them. But that defense misses the point: The Constitution is not just a legal document. It is a didactic one. It doesn’t just set limits to power; it expresses a national ethos. It doesn’t just tell you what you’re not allowed to do; it also suggests what you shouldn’t want to do. The First Amendment allows you to express whatever opinion you want — even, say, advocating the suppression of free speech in others. But a major purpose of the Constitution is to discourage and delegitimize such authoritarian thinking.

Carson later backtracked, saying that he meant opposing someone not because of his identity, ethnicity or faith but because of his ideology — meaning that he wouldn’t want in the White House an Islamist who seeks to impose Shariah law.

Neither would I. Unfortunately, that’s not what Carson had said. In the original interview, he said, “I would not advocate that we put a Muslim in charge of this nation.” It would not have been hard to attach any of the appropriate restrictive adjectives — radical, extreme, Islamist — to the word “Muslim.” He didn’t.

Indeed, Carson gave the correct answer minutes later when he said he wouldn’t apply his presidential religious test to congressional candidates. In that case, “it depends on who that Muslim is and what their policies are.” Which is, of course, the right answer, the American answer, the only possible answer to the same question about a candidate for the presidency.

Carson is not one to cynically pander. Nor do I doubt that his statement about a Muslim president was sincerely felt. But it remains morally outrageous. And, in a general election, politically poisonous. It is certainly damaging to any party when one of its two front-runners denigrates, however thoughtlessly, the nation’s entire Muslim American community.

Particularly when it follows the yeoman work done by the other leading GOP candidate to alienate other large chunks of the citizenry. Three minutes into his campaign, Donald Trump called Mexican-American immigrants rapists who come bringing drugs and crime. He followed that by advocating the deportation of 11 million illegal immigrants. And sealed the deal by chastising Jeb Bush for speaking Spanish in answer to a question posed in Spanish.

Trump’s contretemps with women enjoy even more renown — his attacks on Megyn Kelly (including a retweet calling her a bimbo) and his insulting Carly Fiorina for her looks.

Muslims, Hispanics, women. What next? Who’s left?

It’s a crazy time. One party is knowingly lurching toward disaster, marching inexorably to the coronation of a weak and deeply wounded presidential candidate. Meanwhile, the other party is flamboyantly shooting at itself and gratuitously alienating one significant electoral constituency after another.

And it’s only September. Of 2015.

© 2015, The Washington Post Writers Group