How many different ways can the Republican debates be depressing? Thursday night’s debate in Sioux City, the last before the January 3rd caucus in Iowa, was depressing in many familiar respects: There was Newt Gingrich’s smirking assertion that Barack Obama is a “Saul Alinsky radical”; Rick Santorum’s declaration that Iran is led by “the equal of al Qaeda” (it’s bad enough, Rick!); Mitt Romney’s demagogic patter about American exceptionalism; Rick Perry’s proposal that the legislative branch of the United States should meet for a hundred and forty days every other year, “like in Texas.” (Perry seemed almost amazed by his ability to get through a sentence without catastrophe: “I’m kinda gettin’ where I like these debates!”)

But there’s another subject that always seems to crop up, directly or not, in the Republican debates, and in the campaign, generally—and almost always with an ugly ring.

In terms of civil rights, in terms of the progress of human decency, one of the clearest political victories of 2011—a long and cruelly delayed victory—is the triumph, last June, of marriage equality in the State of New York. This is a victory that will, if we are lucky, spread to many more states and has already enriched the lives of countless gay and lesbian couples. That the remaining Republican candidates (except, notably, Ron Paul) have found so many ways to deride this right, so long in coming, is appalling. History should not forget that at this late date Mitt Romney, Rick Perry, Rick Santorum, Michele Bachmann, and, most recently, Newt Gingrich—politicians who propose to inspire and lead—have pandered to fear and much worse by pledging their support for a Constitutional amendment banning same-sex marriage.

Since Gingrich is still the non-Romney flavor of the moment, let’s focus on him. In an interview with the Des Moines Register this week, the former Speaker of the House, a self-regarding “man of ideas,” ranged freely on the subject. He told the paper that he would also revive the retrograde policy of “don’t ask, don’t tell” in the military, because, “I don’t think that in the military you would particularly want sexual behavior to be an overt issue.”

Gingrich also had things to say on why people have one sexual predilection or another. “I think people have a significant range of choice within a genetic pattern. I don’t believe in genetic determinism, and I don’t think there is any great evidence of genetic determinism,” he theorized. “There are propensities. Are you more likely to do this or more likely to do that? But that doesn’t mean it’s definitional.” When he was asked if someone could choose to be heterosexual, he said, “Look, people choose to be celibate. People choose many things in life. You know, there is a bias in favor of non-celibacy. It’s part of how the species recreates. And yet there is a substantial amount of people who choose celibacy as a religious vocation or for other reasons.” Does it bear repeating why it is more than sickening to hear Newt Gingrich counsel others on the benefits of sexual restraint?

Gingrich, as it happens, has a half-sister, Candace Gingrich-Jones, who is a lesbian, and she recently told ABC News that while her relationship with Gingrich was “cordial” (“uncle-niece-like,”), she “could not support the campaign of somebody who doesn’t think I deserve the same rights as other people.”

Gingrich-Jones is, in fact, married to a woman named Rebecca Jones. Newt Gingrich did not attend the 2009 ceremony; he was on a trip abroad. “I don’t know whether the trip was planned before or after the invitation,” Gingrich-Jones told ABC. “But I’ve known since the nineteen-nineties, he’s said if I ever had a wedding and married a woman he wouldn’t come.” Newt did not send a gift or a card, she added. Gingrich-Jones said she plans to support Obama in the 2012 race: “The things we saw happen in the last four years of the Obama Administration would all, or many of them, go away under a President Gingrich. It would be a huge setback.”

In Sioux City, Mitt Romney wriggled on the issue. He is a coin of many sides. Asked about gay rights, in general, he said, “I do not believe in discriminating against people based on their sexual orientation. Some people do.” He said that when he was governor of Massachusetts, he had a gay member of his administration and would never ask potential judges their sexual orientation. When Rick Santorum said that Romney, despite his opposition to gay marriage, had signed gay-marriage licenses, Romney said, well, he had no choice, because the Massachusetts Supreme Court had ruled gay marriage legal: “I fought it every way I possibly could.”

Photograph by Scott Olson/Getty Images.