Maine Senator Susan Collins, a Republican, on Wednesday endorsed gay marriage.

Collins released a statement on the issue after the Human Rights Campaign (HRC), the nation's largest LGBT rights advocate, endorsed Collins for a fourth term.

“A number of states, including my home state of Maine, have now legalized same-sex marriage, and I agree with that decision,” Collins said.

Ohio Senator Rob Portman was the first GOP senator to make such an endorsement. Portman said in March, 2013 that the issue had become personal for him after his son came out gay. Roughly two weeks later, Illinois Senator Mark Kirk followed suit, saying that after suffering a major stroke he realized that “our time on Earth is limited.” Alaska Senator Lisa Murkowski followed suit last summer.

In endorsing Collins, HRC President Chad Griffin praised Collins' record on gay rights.

“Senator Susan Collins has played a pivotal role in advancing support for LGBT equality – from her dogged support for the repeal of 'Don't Ask, Don't Tell' to her critical vote for the Employment Non-Discrimination Act last year,” Griffin said. “HRC is proud to stand with Senator Collins, and with allies on both sides of the aisle like her, because she firmly believes that every American should be evaluated based on their abilities, and not who they love.”