The selection process for Senator Obama’s running mate has been so secretive that most people in his campaign headquarters still did not know what was going on Friday evening. Democrats were not ruling out the possibility that Mr. Obama could surprise the party with a choice other than Senator Biden.

As intense as the anticipation over Barack Obama’s choice is, it pales next to the hubbub over whether John McCain is going to tap Joe Lieberman, who was Al Gore’s running mate in 2000. This would give Lieberman a unique niche in American history — one politician who was the vice-presidential nominee for both parties. We would speak of it with awe, like that story about the two-headed turtle in Brooklyn.

Senator Obama’s advisers said the candidate all but reached his decision while on vacation in Hawaii. They said the nomination process was unexpectedly intense, and was condensed because Mr. Obama did not want to start actively vetting potential running mates before Senator Hillary Rodham Clinton quit the race in June.