TAMPA, Fla.—Barack Obama radiated confidence and John McCain displayed the grit of an underdog Monday as the presidential rivals reached for the finish line of a two-year marathon with a burst of campaigning across battlegrounds from the Atlantic Coast to Arizona.

“We are one day away from change in America,” said Obama, a Democrat seeking to become the first black president—a dream not nearly as distant on election eve as it once was.

McCain, too, promised to turn the page of the era of George W. Bush, and he warned about his opponent’s intentions. “Sen. Obama is in the far left lane” of politics, he said. “He’s more liberal than a guy who calls himself a Socialist and that’s not easy.”