“Enough is enough. It seems that Senator Brown just has to get out of bed tomorrow to win convincingly. As far as we’re concerned, this race is well and truly over,” said Paddy Power, Ireland’s largest bookmaker, 24 hours before the actual election.

Before shutting down the betting, Mr. Brown had gone from 5-4 odds to 1-5 (meaning if a bettor put down $5, they only stood to make $1 if Mr. Brown wins). The odds against his opponent — Democrat Martha Coakley, the state’s attorney general — soared, from 4-7 to win to 3-1 to lose.