“There’s an old adage about a vat of wine standing next to a vat of sewage. Add a cup of wine to the sewage, and it is still sewage. But add a cup of sewage to the wine, and it is no longer wine but sewage. Is this what Donald Trump has done to our politics?" —Martha Bayles, in the Claremont Review of Books

Yes, as Republicans should remember when their convention opens in less than a month, on the one-year anniversary of Donald Trump’s disparagement of John McCain as unheroic because he was "captured.” McCain was captured (with a broken leg and two broken arms) when North Vietnamese shot down his plane. He chose extra years of torture, refusing to leave when his torturers wanted to release him because he was an admiral’s son.

Trump says, however, that he, too, has been “very brave” by ignoring the danger of venereal disease during his sexual adventures: “It is a dangerous world out there — it’s scary, like Vietnam. Sort of like the Vietnam era. It is my personal Vietnam, I feel like a great and very brave soldier.” He was serious; irony is not in this narcissist’s repertoire. And there is a reason why Britain’s staid Economist magazine refers to Trump’s “look of a roue gone to seed.”

“Every republic,” writes Charles Kesler, professor of government at Claremont McKenna College, “eventually faces what might be called the Weimar problem.” It arrives when a nation’s civic culture has become so debased that the nation no longer has “the virtues necessary to sustain republican government.” Do not dwell on what came after the Weimar republic. But do consider the sufficiency of virtue that the Constitution’s Framers presupposed.

Kesler recalls that James Madison’s notes on the Constitutional Convention contain this from the July 17, 1787, debate on the proposal to have presidents chosen by Congress: Rather than making the president a “creature of the legislature,” Gouverneur Morris favored election by the people. Rejecting the criticism that the people will be “uninformed,” he said: “They will never fail to prefer some man of distinguished character or services; some man … of continental reputation.”

In Trump, Republicans have someone whose reputation is continental only in being broadly known. He illustrates Daniel Boorstin’s definition of a celebrity as someone well-known for his well-knownness. It will be wonderful if Trump tries to translate notoriety into fulfillment of his vow — as carefully considered as anything else about his candidacy — to carry New York and California. He should be taunted into putting his meager campaign funds where his ample mouth is. Every dime or day he squanders on those states will contribute to a redemptive outcome, a defeat so humiliating — so continental — that even Republicans will be edified by it.

Trump’s campaign has less cash ($1.3 million) than some congressional candidates have, so Republican donors have never been more important than they are at this moment. They can save their party by not aiding its nominee.

Events already have called his bluff about funding himself and thereby being uniquely his own man. His wealth is insufficient. Only he knows what he is hiding by being the first presidential nominee in two generations not to release his tax returns. It is reasonable to assume that the returns would refute many of his assertions about his net worth, his charitableness and his supposed business wizardry. They might also reveal some awkwardly small tax payments.

If his fear of speculation about his secrecy becomes greater than his fear of embarrassment from what he is being secretive about, he will release the returns. He should attach to them a copy of his University of Pennsylvania transcript, to confirm his claim that he got the “highest grades possible.” There are skeptics.

Various Republican moral contortionists continue their semantic somersaults about “supporting” but not “endorsing” Trump. In Cleveland, they will point him toward the highest elective office in a country they profess to love but that he calls “a hellhole.” When asked in a 1990 Playboy interview about his historical role models, he mentioned Winston Churchill but enthused about others who led “the ultimate life”:

“I’ve always thought that Louis B. Mayer led the ultimate life, that Flo Ziegfeld led the ultimate life, that men like Darryl Zanuck and Harry Cohn did some creative and beautiful things. The ultimate job for me would have been running MGM in the ‘30s and '40s — pre-television.” Yes, that job, not the one he seeks.

© 2016, Washington Post Writers Group