DENVER — Senators John McCain and Barack Obama have begun recalibrating their strategies for the presidential campaign — and reconsidering some of their basic assumptions about which states and voters are in play — in a contest recast by Mr. McCain’s unexpected selection of Gov. Sarah Palin of Alaska as his running mate.
A day after Mr. McCain announced his decision, catching almost everyone but his inner circle by surprise, both sides were trying to gauge the risks and opportunities of having a young, relatively inexperienced, socially conservative woman on the Republican ticket.
The Obama campaign and the Democratic Party had prepared advertisements and lines of attack directed at the two men who had been most prominently mentioned as vice-presidential possibilities for Mr. McCain — former Gov. Mitt Romney of Massachusetts and Gov. Tim Pawlenty of Minnesota — but had not considered Ms. Palin a likely enough choice to do the same for her. A new advertisement linking President Bush to Mr. McCain was quickly put together, but it contained only a fleeting mention of Ms. Palin.
That tentativeness reflected what Mr. Obama’s advisers said was their struggle to figure out how to challenge the credentials and the ideology of a woman whose candidacy could be embraced by many women as a historic milestone. Once formally nominated at the Republican convention in Minneapolis-St. Paul this week, Ms. Palin, who was elected governor two years ago, will be the second woman chosen by a major party as a vice-presidential candidate.
Mr. Obama’s campaign does not plan to go directly after Ms. Palin in the days ahead. Instead, it is planning to increase its attacks on Mr. McCain for his opposition to pay equity legislation and abortion rights — two issues of paramount concern to many women — as it tries to head off his effort to use Ms. Palin to draw Democratic and independent women who had supported Senator Hillary Rodham Clinton.
Mr. McCain’s advisers said that rallying wavering women would be one of Ms. Palin’s main jobs in the weeks ahead. They said her campaign schedule would take her to areas in swing states like Ohio and Pennsylvania where there were pockets of women who had supported Mrs. Clinton in the primaries.
At the same time, they suggested, Ms. Palin would also be given the task of appealing to evangelical voters, who have long been unenthusiastic about Mr. McCain. In many ways, the choice of Ms. Palin may prove to have been as much an effort to drive up turnout among the Republican base as it was a move to compete for women.
“We had a solid Republican and evangelical base,” said Charlie Black, a senior adviser to Mr. McCain. “But now it’s going to be very intense.”
James C. Dobson, the influential conservative Christian leader who said in the primaries that he could never vote for Mr. McCain, said the selection of Ms. Palin had won him over. If he went into the voting booth today, Mr. Dobson told the talk radio host Dennis Prager on Friday, “I would pull that lever.”
If Ms. Palin motivates evangelicals to rally behind the Republican ticket as they did for Mr. Bush in 2004, it could prove significant in states like Iowa and Ohio, where Republicans won by slim margins in 2004. It could also have an effect in North Carolina, a solidly Republican state that Mr. Obama is trying to win by appealing to black voters and new residents.
Republican leaders in North Carolina, who had been increasingly anxious over Mr. Obama’s intensive efforts there, said they were heartened by the selection of Ms. Palin.
“Our people are excited,” said Linda Daves, the chairwoman of the North Carolina Republican Party. “The social conservatives are one area where she is going to resonate.”
Mr. McCain’s choice of a running mate comes at a pivotal time in the campaign. It follows what even Republicans said was a successful convention here by Mr. Obama. And it comes on the eve of Mr. McCain’s convention, with Republicans nervously watching Hurricane Gustav as it heads into the Gulf of Mexico, an unwelcome reminder of how the Bush White House’s halting response to Hurricane Katrina in 2005 hurt the president and his party politically.
Mr. McCain, in an interview taped for “Fox News Sunday,” said the convention program might be reduced or suspended for a day or two if the storm turned out to be destructive.
Aides to Mr. McCain, who has frequently criticized Mr. Bush’s slow response to Hurricane Katrina, said Saturday he would go to Mississippi on Sunday for an inspection of storm preparations.
With both presidential candidates having filled out their tickets — Mr. Obama traveled Saturday across Ohio with his running mate, Senator Joseph R. Biden Jr. of Delaware — their campaigns have now shifted into high gear.
Mr. Obama’s aides said that they were confident of holding on to all the states Senator John Kerry won against Mr. Bush in 2004 and that they were already well positioned to pick up Iowa and New Mexico, both of which narrowly went to Mr. Bush. The Obama campaign is investing heavily to compete on more challenging terrain for Democrats, including Florida and Virginia.
But Mr. McCain is focusing heavily on taking two big states away from the Democrats: Michigan and Pennsylvania. Both have blocs of white, working-class voters who are anxious about the economy, a group that has given Mr. Obama difficulty and could be receptive to Ms. Palin’s support for gun rights and the portrayal of her as a churchgoing mother of five who shares their values.
Mr. Obama intends to campaign throughout the Republican convention, visiting Indiana, Pennsylvania and Wisconsin.
At a stop on Friday in western Pennsylvania, one of Mr. Obama’s biggest applause lines was reprised from his Denver speech, mocking Mr. McCain for pledging to follow Osama bin Laden to the “gates of hell” but not, in the view of Democrats, supporting sufficient military force in Afghanistan to capture him.
Mr. Obama this weekend began running the advertisement invoking Ms. Palin and linking Mr. McCain and Mr. Bush. In the advertisement, as images of Mr. McCain with Ms. Palin and then with Mr. Bush are shown, an announcer says, “While this may be his running mate, America knows this is John McCain’s agenda.”
But the campaign is about to turn to state-specific commercials tailored to local issues, possibly including one on a proposed national relief fund for hurricane insurance that is popular in Florida, said David Plouffe, Mr. Obama’s campaign manager.
Mr. Obama’s advisers said that compared with the mountains of data they had gathered on Mr. Pawlenty and Mr. Romney, they had far less information on Ms. Palin. Their dossier consisted of a thin document based mainly on her run for governor and newspaper clips.
Aides said the party staff members and allies in Alaska would sort through public documents relating to Ms. Palin’s time in the governor’s mansion, her two terms as mayor of Wasilla, Alaska, and her two terms as a member of the Wasilla City Council.
Democrats were not the only ones regrouping. Republican officials said that though they had time to collect surface-level material on Ms. Palin and her husband, they had done no examination of the rest of her family.
Beyond that, Republican organizers said the convention aides in charge of reviewing every speech delivered from the lectern are now on the watch for blunt attacks on Mr. Obama’s readiness to lead, and reviewing how much to emphasize what had been the convention theme: “Not Ready ’08.” They are aware that such criticism in a high-profile setting would provide an opportunity for Democrats to make the same charge against Ms. Palin, who has almost no foreign policy experience and has been governor for just 20 months.
Several Republican delegates said they too were shocked by the selection of Ms. Palin and, while they wished her well, were deeply concerned that she did not have the experience in foreign policy or national security to be commander in chief.
“We’ve been told for the last few months that experience is what matters most in the next White House,” said John Scates, a delegate from St. Louis. “But McCain is picking someone whose experience is little to nothing or, at best, unknown.”
In the days ahead, Mr. Obama’s advisers said they would not just seek to define Ms. Palin as extremely conservative on issues like abortion and raise questions about her credentials as part of a larger effort to challenge Mr. McCain’s judgment. They will also argue that Mr. McCain’s decision would prove to be a mistake in terms of appealing to women and that it would hurt him in important battlegrounds like the Philadelphia suburbs.
“In terms of the classic suburbs, it’s a bomb,” said Marcel L. Groen, the chairman of the Democratic Party of Montgomery County, outside Philadelphia. “So far as suburban woman go, this will not help McCain at all: they’re pro-choice and anti-gun.”
It is complicated terrain, aides to Mr. Obama and Mr. McCain acknowledged. Any perception that Mr. Obama or his supporters were trying to tear down Ms. Palin could renew anger among supporters of Mrs. Clinton.
“I can’t imagine the Obama team will spend their time on Palin; they’ll spend their time with their negative ads attacking McCain and Bush,” said Mandy Grunwald, Mrs. Clinton’s chief advertising strategist. “You always have to be careful not to rally people to her side by attacking too much.”
Republicans said Ms. Palin would provide an outlet for women angered at what they said was the poor treatment of Mrs. Clinton by the Obama campaign, the Democratic Party leadership and the news media. Nicolle Wallace, a senior adviser to Mr. McCain, said: “I think the public pretty much accepts the fact that they played pretty dirty and that sexism played a role in the primary.”
Mr. Obama’s campaign has moved on a variety of fronts to increase his appeal to women. Leading women in battleground states are being mobilized, and a disproportionate number of female surrogates are being sent to argue for him on television. They are being asked to focus on abortion rights and pay equity, aides said, and to steer clear of criticizing Ms. Palin as having limited experience in elected politics and government.
And Mrs. Clinton is likely to play an even more active role on behalf of Mr. Obama in the fall campaign, her aides said, because of Ms. Palin. She is expected to participate in television appearances, fund-raisers and conference calls with reporters to rebut efforts by the McCain campaign to court her supporters.
Mr. Obama’s campaign said there were now about 18 states in play, including Alaska. In interviews, campaign officials said they would compete there, despite the fact that the name of its very popular governor will appear on the ballot.
Mr. McCain’s advisers laughed at that. “We’re scared to death about Alaska,” Mr. Black said.