As no Republican has ever won the presidency without winning Ohio, it was seen in particular as a "must-win" state for McCain.
He did not try to explain his third-place showing in what he had insisted was a must-win state.
Both Mr. Kerry and President Bush view Ohio as one of a handful of must-win states this fall.
Dr. Dean has called Wisconsin a must-win state.
Vetoing it, however, or letting it die this Saturday, would undermine candidate Bush's popularity in must-win Western states.
Gingrich, talking about his own chances, described South Carolina as "a must-win" state.
Likewise, in a fall face-off with President Clinton, he would be a formidable obstacle in California, a must-win state because it has the most electoral votes.
Hearings are under way in Oregon and are set to start on Monday in California, considered a must-win state for Batus.
In general, though, he is expected to hurt President Bush in Texas and Florida, two must-win states for the Republicans.
Considered a must-win state, with its vital 21 electoral votes, it was too close to call on election eve.