Nevada Senator John Ensign admitted Tuesday he had an affair with a former staffer, the Los Angeles Times reported.

Ensign, a gay rights opponent, was considered a rising star of the Republican party and possible presidential material.

“If there was ever anything that I could take back in my life, this would be it,” Ensign said Tuesday afternoon during a news conference in Las Vegas.

The fifty-one-year-old Republican indicated he would remain in office after stating he had participated in a nine-month affair in 2008 with a woman who worked for his Senate campaign. The woman's husband also worked for the senator.

In 2004, Ensign urged Congress to pass a constitutional amendment banning gay marriage, saying “Marriage is the cornerstone on which our society was founded.”

Ensign also chided Idaho Senator Larry Craig after his arrest in a Minneapolis men's room for lewd behavior. He called Craig a “disgrace,” and called on him to resign. Craig served the remainder of his term but never admitted being gay.

The Human Rights Campaign, the nation's largest gay and lesbian rights advocate, gives Ensign a zero for his support of gay rights. Ensign's score on the group's Congressional Scorecard has steadily dropped from 25 in 2007 to zero in 2009.

After making his announcement, Ensign did not take questions from the media.