Robert Byrd was first elected to Congress when Harry Truman was serving in the White House and segregationists held enough sway in the Senate to block even the mildest civil rights laws.

Byrd has died, at age 92, as a senator serving as an ally and champion of the nation’s first African-American president.

America’s journey was Byrd’s journey. Indeed, Byrd’s transit of the arc of history provides one of the most redemptive stories of this nation’s progress.

Infamously, the West Virginia Democrat was in his youth a member of the Ku Klux Klan in his native West Virginia. Even when he came to the House, after his election in 1952, and the Senate, after his election in 1958, he served as a segregationist. He voted against the Civil Rights and Voting Rights Acts, stances that caused significant opposition in the Democratic Caucus to his initial candidacies for leadership posts. Yet Byrd remained a Democrat, rejecting the easy road of switching, as so many other Southern and border-state Democrats did, to a Republican Party that—as part of Richard Nixon’s "Southern strategy"—was welcoming old segregationists with open arms.

His fellow Democratic senators eventually accepted the sincerity of Byrd’s rejections of his past positions and elected him Senate majority leader, a position he held until 1988, when the New York Times noted that he was leaving the post “for reasons of age." As it happened, Byrd remained in the Senate for the better part of a quarter-century more, ending his career as one of the most ardent supporters of Obama’s election and presidency.

I covered Byrd during much of that last quarter century and, like the vast majority of his fellow senators, developed an appreciation for the sincerity of the man’s rejection of the past—his own and his country’s. In many senses, Byrd’s own transformation from one senator among many to the unique figure he became in the history of the chamber and the country began during the Watergate era, when the senator’s pointed questioning of White House appointees was widely credited with having forced the opening that led to John Dean’s testimony and the end of Richard Nixon’s presidency. But his final transformation came as another authoritarian president, George W. Bush, sought to draw the nation into undeclared and unnecessary war.

Byrd had supported the Vietnamese mission of presidents Johnson and Nixon and, like many senators who made the same mistake, he had come to recognize the importance of asserting a Congressional check and balance on presidential warmaking. The speeches that the senior senator delivered in opposition to Bush’s Iraq proposal were epic in character and they thrilled antiwar activists who came to understand, on Byrd’s instruction, that they were the true defenders of the Constitution.

The great measure of Byrd’s commitment came as the Bush presidency was ending and Democrats were preparing to nominate a candidate to replace the drift and lawlessness of the Bush-Cheney interregnum.

After New York Senator Hillary Clinton’s late-stage victories in a number of Democratic primaries, Byrd has a choice to make. Clinton was dramatically more popular in West Virginia and neighboring states such as Kentucky than the young senator from Illinois, Barack Obama. And Byrd could easily have backed the woman who had courted him from the time of her election to the Senate in 2000.

Despite the sentiment for Clinton in his home state, however, Byrd explained that he was of the view that the election of a president was about the future of the nation and the world. And the Constitution-toting senator declared that "the stakes this November could not be higher."

With that in mind, Byrd gave his endorsement to Obama.

"Barack Obama is a noble-hearted patriot and humble Christian, and he has my full faith and support," said the senator, who had been involved in Democratic politics long enough to have made the long transit from supporting segregationism to supporting an African-American for president.

Byrd’s support for Obama was grounded in what for both men had been their signature stance during the Bush years: opposition to the war in Iraq.

Describing Obama as "a shining young statesman, who possesses the personal temperament and courage necessary to extricate our country from this costly misadventure in Iraq, and to lead our nation at this challenging time in history," Byrd explained that "as people all across this great nation know, I have been one of the most outspoken opponents of the Bush administration’s misguided war in Iraq and its saber rattling around the globe. With the Bush administration’s latest request to fund this ongoing war in Iraq without any attempt to start bringing our troops home, the issue of the upcoming presidential contest has been weighing heavily on my heart. The loss of life continues and the sons and daughters of tens of thousands of American families remain in harm’s way every day."

Leaving little doubt that it was Obama’s record of opposing the war that made the Illinoisan preferable to Clinton, Byrd concluded, "After a great deal of thought, consideration and prayer over the situation in Iraq, I have decided that, as a super-delegate to the Democratic National Convention, I will cast my vote for Senator Barack Obama for President."

In the fall, Byrd campaigned hard for Obama. And upon his election, Obama would thank the senior senator with a combination of warmth and respect that illustrated the bond that these two very different men had made.

Ultimately, Byrd’s support of Obama meant more for him than for the president, who would say on his friend and mentor’s passing that the senator "had the courage to stand firm in his principles, but also the courage to change over time."

It turned a page in the American history that remains incomplete.

Remarkably, Robert Byrd was born just one lifetime away from the greatest of his many heroes in the founding circle, Thomas Jefferson.

The author of the Declaration of Independence and the nation’s third president died ninety-one years before Byrd was born.

Jefferson did not live long enough for circumstance or opportunity to bend the arc of history fully in his favor. He died having failed to make real the promise of the declaration—that “all men are created equal.” His final statements recognized his personal failure, and that of the nation he had forged, when it came to the questions of human bondage and racial equality.

Robert Byrd lived long enough. He buried the past before his own burial. He died as Jefferson would have wanted—as a redeemed man, steeped in history but of the present.