Despite that, McCain will question Obama's credentials to lead the United States in a dangerous world. Presidential historian Richard Norton Smith says McCain needs "to take advantage of the uncertainties people may feel about Obama."
But Smith says McCain must "be very careful how he does that," lest the critique take on racial overtones.
Republicans have settled on a theme for their campaign against Obama and in Denver named a website after it: NotReady08.
However, with Palin on the GOP ticket, that argument just became more difficult to make. Democrats note that Palin has been governor for just 20 months and has traveled only to Canada, Germany and the Iraqi-Kuwaiti border.
In an interview with CNBC several weeks before she was chosen by McCain, Palin said she was "used to being very productive" and asked, "What is it exactly that the VP does every day?"
McCain "needs to make people feel Obama is not qualified to be president" by way of experience or judgment, says Walter Russell Mead, a senior fellow with the Council on Foreign Relations.
2. Play the maverick
McCain came to national prominence eight years ago with his "Straight Talk Express" campaign for president, but his reputation for independence had been building for decades. He has opposed the majority in his party on tax cuts, "pork-barrel" spending, immigration, global warming and the overhaul of the campaign-finance system.
Those efforts in the past have attracted moderate Democrats and independents who jump from one party to the other.
Now McCain advocates extending Bush's tax cuts and drilling offshore, stances in line with party conservatives. Democrats have cast him as representing what would amount to a third term for Bush.
"He has to return to that sense of crusading maverick that made him the darling of independents and floating voters everywhere," says pollster Frank Luntz, who has worked with Republicans.
Independents want someone who "can get us beyond the partisan divide," says former Democratic congressman Tim Penny of Minnesota, a McCain backer.
McCain must not ignore elements of his own party who view his willingness to work with Democrats with suspicion. Economic conservatives, such as the Club for Growth, have condemned his votes in 2001 and 2003 against President Bush's tax cuts. Social conservatives, such as the Family Research Council, are pleased that the GOP ticket is opposed to abortion rights but are concerned that McCain supports more government funding for stem-cell research.
"There is an authentic McCain voice on these issues," says Charmaine Yoest, president of Americans United for Life. "He has to find it and use it."
3. Avoid the 'McBush' label
Shielding himself from an unpopular Republican president is "challenge No. 1" for McCain, says Jack Pitney, a government professor at Claremont McKenna College near Los Angeles. He says McCain needs to stay busy, "laying out his own plans and staying away from the 'B word' as much as possible."
That won't be easy. Democrats are billing McCain as "More of the Same" at their media center here, featuring a photo of Bush and McCain in an awkward hug. They cite McCain's ardent support for the Iraq war and his record of backing Bush's policies, which rose to 95% last year, according to the non-partisan Congressional Quarterly magazine.