I can't say it better than the candidate himself:
"Listening to Senator Byrd I felt with full force all the essential contradictions of me in this new place, with its marble busts, its arcane traditions, its memories and its ghosts. I pondered the fact that, according to his own autobiography, Senator Byrd had received his first taste of leadership in his early twenties, as a member of the Raleigh County Ku Klux Klan, an association that he had long disavowed, an error he attributed—no doubt correctly—to the time and place in which he'd been raised, but which continued to surface as an issue throughout his career. I thought about how he had joined other giants of the Senate, like J. William Fulbright of Arkansas and Richard Russell of Georgia, in Southern resistance to civil rights legislation. I wondered if this would matter to the liberals who now lionized Senator Byrd for his principled opposition to the Iraq War resolution—the MoveOn.org crowd, the heirs of the political counterculture the senator had spent much of his career disdaining."
"I wondered if it should matter. Senator Byrd's life—like most of ours—has been the struggle of warring impulses, a twining of darkness and light. And in that sense I realized that he really was a proper emblem for the Senate, whose rules and design reflect the grand compromise of America's founding: the bargain between Northern states and Southern states, the Senate's role as a guardian against the passions of the moment, a defender of minority rights and state sovereignty, but also a tool to protect the wealthy from the rabble, and assure slaveholders of noninterference with their peculiar institution. Stamped into the very fiber of the Senate, within its genetic code, was the same contest between power and principle that characterized America as a whole, a lasting expression of that great debate among a few brilliant, flawed men that had concluded with the creation of a form of government unique in its genius—yet blind to the whip and the chain."
Barack Obama, The Audacity of Hope
Robert Byrd, now 90 years old and the longest serving senator in history, endorsed Barack Obama for president today. It would have meant more a week ago, before Obama was whomped in Byrd's home state. Byrd, beloved to the point of near-worship in West Virginia, might have been the one person who could have softened that defeat. But as with many other things about Byrd, it's better late than never.