It is not unusual for protesters motivated by personal stories to show up at hotly contested campaigns for elections, like the one taking place on Tuesday for Alabama’s Senate seat.

William Nathan Mathis, a 74-year-old Alabama peanut farmer, was one of them.

When he appeared at a rally for Roy Moore, the Republican candidate, in Alabama’s Wiregrass region on Monday night, Mr. Mathis said in an interview on Tuesday, it was not to cheer the candidate on. He was carrying a placard and a searing memory of a March night in 1995, when he discovered the body of his 23-year-old gay daughter, Patti Sue, after she committed suicide.

“Judge Roy Moore called my daughter Patti Sue Mathis a pervert because she was gay,” Mr. Mathis’s hand-lettered placard said. “A 32-year old Roy Moore dated teenage girls ages 14 to 17. So that makes him a pervert of the worst kind.”

“How is my daughter a pervert just because she is gay?” he told reporters. “I don’t know what I will accomplish. I really don’t. I had mixed emotions about coming. But somebody needs to speak up, and if it is all to no avail, so be it.”

Mr. Mathis’s appearance at the rally was the latest bit of theatrics in the volatile campaign period pitting Mr. Moore, who has denied allegations of sexual misconduct, against Doug Jones, a Democrat. It also highlighted some of the most contentious issues that have dogged Mr. Moore, a staunch evangelical Christian who has condemned same-sex relations, at the last rally before Tuesday’s voting.

Mr. Mathis’s stakeout, as he held up a poster of his daughter in basketball gear, drew extensive media coverage, and his remarks on video were viewed nearly 3 million times online.

“I was anti-gay myself,” he told reporters. “I said bad things to my daughter myself, which I regret.” Read more via New York Times

Referring to Mr. Moore, he added: “He said all gay people are perverts, abominations. That’s not true. We don’t need a person like this in Washington. That’s why I am here.”