As Twitchy has discovered, not only are people “evolving” in their stand on same-sex marriage — the public’s reactions to each evolution are evolving as well. Sen. Claire McCaskill (D-Mo.) announced her support last night and was lauded as a hero. Today, just before the Supreme Court begins hearing arguments on same-sex marriage, Sen. Mark Warner (D-Va.) took to Facebook to announce that he had evolved as well. (He even used the word “evolved” in his post.)

I support marriage equality because it is the fair and right thing to do. Like many Virginians and Americans, my views on gay marriage have evolved, and this is the inevitable extension of my efforts to promote equality and opportunity for everyone. I was proud to be the first Virginia governor to extend anti-discrimination protections to LGBT state workers. In 2010, I supported an end to the military’s ‘don’t ask, don’t tell’ policy, and earlier this month I signed an amicus brief urging the repeal of DOMA. I believe we should continue working to expand equal rights and opportunities for all Americans.

Warner has the (D) shield following his name, so he’s not likely to be attacked for changing his position as Ohio Republican Sen. Rob Portman was. But how late is too late to been seen as “authentically” supporting gay marriage? Mother Jones reporter Tim Murphy has an idea.

Sunday might have been the unofficial deadline, though.