The presidential contest is being fought largely on what has been Republican turf, with Obama leading or running even in such states as Ohio, Virginia and Colorado.

If that continues, it should work to Obama's advantage, although McCain hopes to thwart his rival by removing Michigan and Pennsylvania from the Democratic column.

The tilt of the race is evident in looking at the toss-up states. According to the nonpartisan Web site RealClearPolitics.com, there are 11. And just two - Michigan and New Hampshire - went for John Kerry in 2004.

The rest were Bush states, including such longtime GOP strongholds as Indiana and North Carolina.

David Plouffe, Obama's campaign manager, looks at the map and sees "a huge range of possibilities to get to 270," the winning number of electoral votes. He has told reporters that he was "simply not going to wake up on [Election Day] worried about one state."

A confident Obama spent last week in states that President Bush took twice: Missouri, Ohio, Colorado, North Dakota and Montana.

If Obama wins everywhere the Democrats won four years ago, he'll have 252 electoral votes and could go over the top by taking Ohio or Florida or a combination of smaller states in the West, South and Midwest.

As for McCain, unless he can make inroads into Democratic turf, he'll spend the autumn playing defense, trying to hold off Obama in the red states.

In the view of Republican strategists, McCain's distinctive political profile and Obama's relative weakness with working-class whites give the Arizona senator a shot at Michigan and Pennsylvania, both of which have gone Democratic four times in a row.

"No doubt the environment is very challenging for Republicans by just about every measure," said Michael DuHaime, senior adviser for political operations at the Republican National Committee. "Given that, it's encouraging that we have a candidate with the ability to bring in independents, moderate Republicans and swing Democrats."

A lot can change between now and Nov. 4. Still to come are the vice presidential selections, the conventions, the debates, and changes in the price of oil, the economy, and the war in Iraq.

"If the national race is mid- to high single digits for Obama, as it seems right now, it'll be an Electoral College blowout or close to it," said Peter Brown, analyst for the Quinnipiac University Polling Institute, which surveys swing states. "But if it narrows, the electoral geography gets much more interesting."

Here's the current Electoral College outlook.

Midwest. For both campaigns, no region looms larger. Two states, Ohio and Michigan, figure to be key.

No Republican has won the presidency without Ohio. Ever. If Obama can take it this year - and he did not do well in the Ohio primary - it's hard to see how McCain can win the White House. Some polls have the Illinois senator ahead there now.

Then there's Michigan, home to the original "Reagan Democrats." Of all the big states Kerry captured in 2004, it looks to be the most promising for McCain now.

Obama was hurt there by the dispute over party rules that led him to skip the Michigan primary. It's a must-win; he has a slim lead in the polls.

In pursuit of his hopes of expanding the playing field, Obama has designs on two unlikely Midwestern targets.

One is Indiana, which has voted Democratic only once since 1936; the polls are even there. Another is North Dakota, which Obama won big in the caucuses. He's running television commercials in both states.