Delaware was won by Democratic nominee John Kerry by a 7.6% margin of victory. Prior to the election, all 12 news organizations handicapping the election predicted that Kerry would win Delaware, though with varying degrees of confidence; the First State was a key bellwether for much of the 20th century, but Al Gore's comfortable victory four years earlier amidst a national loss marked its move towards the Democratic Party. Kerry won Delaware without either campaign seriously contesting it, but with a 5.5% swing to Bush compared to Gore's performance in 2000. The swing was largely concentrated in Kent and Sussex Counties, in which Bush's margins increased by double digits; New Castle County, the state's most populous, only swung about a point to Bush, continuing its consolidation as the state's Democratic base.
As of 2020, this is the last election in which Delaware was decided by a single-digit margin, and the first time since 1948 that Delaware has not backed the national popular vote winner. Bush became the first Republican since 1880 to win the popular vote without Delaware, and the last to win 60% of the vote in any county in the state (namely Sussex). Bush was the first Republican since Abraham Lincoln to win two terms without ever carrying the state.
