WaPo’s Fix has this (and more) to say about Warner’s decision to skip 2008:

The most obvious winner from the Warner news is Indiana Sen. Evan Bayh. Bayh and Warner shared much of the same ideological territory — moderate, consensus builders elected in red states. After helping Gov. Tim Kaine(D) win the governorship in 2005, Warner became the “it” boy of national politics — the candidate seen as most likely to emerge as the alternative to New York Sen. Hillary Rodham Clinton(D).

Warner’s ascent came at the expense of Bayh, who found much of the air sucked out of his candidacy.

No longer. Party insiders say that there was a major behind-the-scenes fight for donors and activists between Bayh and Warner.

Well, that sounds familiar…