In May of 2008–despite considerable lobbying from Hillary Clinton, with whom he had a personal friendship–the late West Virginia Senator Robert Byrd endorsed Barack Obama in the Democratic primary, just four days after his state had voted overwhelmingly for Clinton.

As Sam Stein notes, it was a seminal endorsement for both Byrd and Obama, whose team did its best to publicize the symbolism of a former KKK member throwing his support to the man who would become the first black president.

Clinton had become friends with Byrd during her time in the Senate, and had even lunched with Byrd and Clinton’s mother, who came to admire him while monitoring C-SPAN for her daughter’s floor appearances.

This morning, Secretary of State Hillary Clinton put out her own statement eulogizing Byrd as a “friend and mentor” as “a man of unsurpassing eloquence and nobility.”

“It is almost impossible to imagine the United States Senate without Robert Byrd. He was not just its longest serving member, he was its heart and soul. From my first day in the Senate, I sought out his guidance, and he was always generous with his time and his wisdom,” Clinton wrote.

“I will remember him most for a heartfelt comment he made to me in the dark days following 9/11, when my state of New York was reeling and we were scrambling to provide support and relief. ‘Think of me as the third senator from New York,’ he said. And he meant it. Thanks to the leadership of Senator Byrd, who chaired the Appropriations Committee, New Yorkers got the help they needed. I will never forget his devotion and his friendship in that critical time.”

Here’s her full statement: