Snowe, who had been elected to both of her previous terms by approximately 2 to 1 margins, had never lost an election. The reason why Snowe won by a landslide even when Democrats were winning across the country is because she is a centrist Republican and thus has a very high approval rating in Maine. Meanwhile, her Democratic opponent in the 2006 election, Jean Hay Bright, had never been elected to political office.
Democrats' best hope for taking the seat was that Snowe would retire rather than run in 2006, but there was never any indication that Snowe seriously considered not running for re-election.
The filing deadline for major party candidates was March 15, 2006. The primary was held on June 13, 2006. Olympia Snowe was unopposed for the Republican nomination; Jean Hay Bright narrowly won the Democratic nod with 50.7% of the vote against Eric Mehnert.
Hay Bright announced her candidacy in May 2005. Hay Bright was previously an unsuccessful candidate for the Democratic nomination to the House in 1994 and the Senate in 1996.
The race had been called by FOX News for the Republican incumbent Olympia Snowe 23 minutes after the polls had closed. Snowe won re-election by a greater margin than any U.S. Senator that cycle except Indiana'sRichard Lugar, who faced only a Libertarian opponent.