“While their policies would take America in the wrong direction, Governor Palin will add an important new voice to the debate,” she said.
Still, some Democrats insisted that the choice of Mrs. Palin may have handed the election to Mr. Obama.
“This pick takes the experience hit on Obama off the table,” said Democratic strategist Liz Chadderdon. “This is done. I am getting out the ‘04 inaugural gown I didnt get to wear out and sending it to the cleaners.”
But Republicans like political strategist Scott Reed called Mrs. Palin an excellent choice for pointing up contrasts with the Democratic ticket.
“Governor Palin has more executive-level experience than Obama and Biden combined,” he said.
In making his pick, Mr. McCain passed over several more prominent prospects who had figured in speculation for months — Minnesota Gov. Tim Pawlenty, former Massachusetts Gov. Mitt Romney and former Pennsylvania Gov. Tom Ridge among them.
Mrs. Palin flew overnight to an airport in Ohio near Dayton, and even as she awaited her formal introduction, some aides said they had believed she was at home in Alaska.
• Ralph Z. Hallow reported from Minneapolis, Minn. Christine Bellantoni, reporting from Monaca, Pa., contributed to this report.