As in the past two campaigns, four big states — Pennsylvania, Michigan, Ohio and Florida — are expected to dominate the attention of the candidates. Democrats won the first two in both 2000 and 2004; Republicans won the other two both times.

Additionally, there will be battles in a group of smaller states now seen by the campaigns as most vulnerable to shifting sides. Five states that went for President Bush in 2004 are now high on the list of potential Obama states: Iowa, New Mexico, Colorado, Nevada and Virginia. Two states that went for Sen. John F. Kerry are top targets of McCain's campaign: Wisconsin and New Hampshire.

Both candidates brought their campaigns to New Hampshire this weekend, signaling the importance of a state with just four electoral votes. Four years ago, the State was one of three states that switched allegiance between the campaigns of 2000 and 2004.

Obama advisers say they still have their sights on a number of Republican strongholds, among them Georgia, North Carolina, Indiana, Montana and North Dakota. With the benefit of a massive fundraising operation — the Obama campaign announced Sunday it raised a record $66 million in August — and huge numbers of volunteers, the Democratic nominee has the luxury to compete in states this fall that past campaigns would have had to abandon.

But Republicans and some Democratic strategists not associated with the Obama campaign say the overall electoral map has become more familiar in the past few weeks. One reason is McCain's selection of Alaska Gov. Sarah Palin as his vice presidential running mate. Her choice has helped to harden some of the red-and-blue political divisions of past years, dampening Obama's hopes of picking off some solid GOP states.

Reviewing the state of play a week after the Republican convention ended, McCain pollster Bill McInturff declared: “Obama's campaign's effort to extend the electoral map has largely failed. We once again have a pretty conventional and expected list of tossup states that will decide the election.”

Steve Hildebrand, deputy campaign manager for Obama, disagreed, saying there has been no contraction of the Democratic nominee's ambitions to provide as many avenues as possible to the 270 electoral votes needed to win the election. “Other than Alaska being much less likely to be a competitive state because of Sarah Palin, we have not seen any reason to believe that we should shrink the map,” he said.