Washington ? At the age of 88, Sen. Robert Byrd on Monday became the longest-serving senator in history, a milestone in a career that once put him on Richard Nixon’s short list for the Supreme Court and now makes him an icon of the left.

Byrd, with 17,327 days of service since 1959 as a Democratic senator from West Virginia, has eclipsed the late Sen. Strom Thurmond, R-S.C., once the epitome of longevity.

In that time, Byrd has exemplified political evolution. Once an opponent of civil rights legislation who embraced the conservatism of Southern Democrats, he’s now a darling of the liberal Internet blogosphere, where his floor speeches denouncing the war in Iraq are passed around Web audiences at the touch of a button.

Last year, he raised $800,000 through the help of MoveOn.org, the Internet-driven liberal movement launched in 1998 to fight the impeachment of President Clinton.

Reared in West Virginia coal country, he’s one of the last true orators. He quotes Cicero and cites the Constitution from memory. He’s been the Senate’s majority leader and its minority leader. But his greatest congressional legacy is as protector of the Senate, its prerogatives and traditions.