Sen. Robert Byrd, D-W.Va., has just announced that he's endorsing Barack Obama for president. In a statement, Byrd -- the longest-serving senator in U.S. history -- said:

This Democratic primary campaign has been tough and competitive. I had no intention of involving myself in the Democratic campaign for President in the midst of West Virginia's primary election. But the stakes this November could not be higher.

After a great deal of thought, consideration and prayer over the situation in Iraq, I have decided that, as a superdelegate to the Democratic National Convention, I will cast my vote for Senator Barack Obama for President. Both Senators Clinton and Obama are extraordinary individuals, whose integrity, honor, love for this country and strong belief in our Constitution I deeply respect.

Byrd's endorsement carries some symbolism beyond just his lengthy tenure. As Republicans are fond of pointing out, Byrd was once a member of the Ku Klux Klan; indeed, in the early 1940s, he was a leader of his local chapter. He has spent many years since apologizing for his membership in the Klan: In 2005, he said, "I know now I was wrong. Intolerance had no place in America. I apologized a thousand times ... and I don't mind apologizing over and over again. I can't erase what happened."