It's quite a career, and Eugene Robinson's piece in the Washington Post argues that it's a story of redemption. As far as race goes, it is.
Byrd's early career is covered in the slime of racism, as he joined with fellow racist Strom Thurmond and other "Dixiecrats" in an effort to deny human rights and legal protection to African Americans. Thurmond, who died in 2003, switched parties in 1964 in recognition that the opposition to human rights would be based in the Republican Party, but Byrd for some reason remained a Democrat. It could be that West Virginia's Democratic vote was more influenced by union solidarity than by racist solidarity (not that the two didn't and don't overlap), whereas the deep South had more or less kept the working class in their place by enforcing statutes cynically called "right to work."
Byrd remained sympathetic to racist scum and aligned himself with them throughout the 1960's (although he did vote for the Civil Rights Act of 1968). The parallels with Strom Thurmond go beyond their early camaraderie in opposition to federal Civil Rights legislation, and I'm certain that comparing and contrasting the two will be an exercise for columnists and school kids alike (if they even teach civics or government in schools anymore...we are really a nation that doesn't like to understand our government). Both Thurmond and Byrd voted for the federal holiday for Martin Luther King, Jr., but only Byrd renounced his earlier racist views (a renunciation that seemed heartfelt and at the same time a struggle, much like a recovering alcoholic struggles daily with the disease), while Thurmond hid behind the smoke screen of "states rights," a bullshit argument in the arena of equal protection under the law if ever there was one.
Byrd memorably opposed the abdication of Congressional power in the buildup to the Iraq War, when the rest of Congress (with few exceptions) voted to hand over a blank check to then-President Bush in prosecution of his pet war. Byrd correctly labeled it a "war of choice," but that didn't keep the majority of scared-shitless Senate Democrats and all but one Republican from eschewing their obligations to the nation to rein in an overzealous executive branch.
However, Byrd should also be remembered for his social conservatism; yes, he changed his mind on race relations and repeatedly apologized in public for his earlier racist actions. However, he continued to oppose civil rights for other groups, including his backing of the so-called Defense of Marriage Act (which would be more properly called the Limitation of Marriage Act):
''The drive for same-sex marriage,'' said Senator Robert C. Byrd, Democrat of West Virginia, ''is, in effect, an effort to make a sneak attack on society by encoding this aberrant behavior in legal form before society itself has decided it should be legal.
''Let us defend the oldest institution, the institution of marriage between male and female as set forth in the Holy Bible.''
So much for the separation of church and state, when the acknowledged Constitutional expert relies on a religious text and not the U.S. Constitution for legislative advice.
So let's applaud Byrd for his willingness to abandon one arena of ignorance, but let's not lionize him as a friend of equal rights for all.