Political observers have always known that the open 50th Congressional District seat would be a hardball affair. The stakes are high and the candidates running have major differences. But former Rep. Darrell Issa’s new attack ad targeting fellow Republican Carl DeMaio, the former San Diego councilman and talk show host, is despicable. It’s nominally about who is the more devoted supporter of President Donald Trump and who is a bigger critic of illegal immigration. Yet the two headlines from printed stories the ad shows aren’t about these themes. Instead, they both identify DeMaio as gay.

Clearly, Issa believes pointing out this fact about his opponent will help him win some voters in the 50th, which includes East County and most of noncoastal North County. It’s also clear he’s lost some of his humanity. Polls show a growing, overwhelming acceptance of gay marriage and gay rights — which after all are human rights — but homophobia remains a problem. Thursday, Issa was unapologetic.

It’s a searing comment on Issa’s character that the former Vista congressman would try to take advantage of hateful views of the LGBTQ+ community. None other than Tony Krvaric, the chairman of the Republican Party of San Diego County, told an editorial writer the ad was “Highly inappropriate. We encourage all candidates to stick to the issues.”

Gay-baiting is unacceptable and unforgivable.