Kaine spread the word that he had learned his political fate in a telephone call from Obama.
The normally loquacious Biden maintained a low profile as associates said they believed - but did not know - that he would be tapped. They added they had been asked to stand by in case their help was needed.
Additionally, several associates of Obama - including some at his campaign headquarters in Chicago - said they believed Biden was the choice, though they cautioned they had not been told directly.