Today's debate at Hofstra University in Hempstead, N.Y., is slated to focus entirely on the economy and domestic policy. The candidates will be seated at a table with moderator Bob Schieffer of CBS.

Both presidential contenders have used the previous debates to make and remake their main campaign points, frequently sidestepping direct questions such as how they would have to scale back their long lists of campaign promises in light of the economic crisis.

Advisers for each candidate say he will use the final debate to lay out his vision for the country and promote his economic policies while drawing differences with his opponent.

Character attacks — subtle or not — also could occur.

Obama has increasingly labeled McCain "erratic" and "lurching" during the economic crisis. The words suggest unsteadiness on the part of the 72-year-old four-term senator.

The Democrat's campaign released a pre-debate memo Tuesday that argued McCain was "ill-equipped" to lead during this crisis, saying his response "has careened, sometimes changing course within the span of a single day."

McCain has accused Obama of lying about his association with 1960s radical William Ayers, a founder of the violent anti-war group Weather Underground. Obama was 8 years old when the Weather Underground claimed responsibility for a series of bombings. Now a professor in Chicago, Ayers hosted a meet-the-candidate session at his home for Obama as he prepared to run for the state Senate. Later, the two worked with the same charity and social-service organizations in Chicago.

McCain has softened that attack on the campaign trail in recent days, though not in his TV and radio ads.

His campaign assailed Obama's on Tuesday for its "failure to explain how it is that Barack Obama carried on a decade-long friendship with a man who sought to topple the U.S. government through violence."

McCain has solidified and energized his base of Republican voters, but he has problems with his support among swing-voting independents. A recent Associated Press-GfK Poll showed them divided about evenly between the two candidates. That's a problem for McCain because Democrats decisively outnumber Republicans this year.

Compounding McCain's woes, new Quinnipiac University polls released Tuesday showed Obama leading by double digits in two states that Democrat John Kerry won four years ago and that McCain is trying to put in his column this year — Wisconsin and Minnesota — as well as in Michigan, which McCain abandoned earlier this month.

Other poll results released Tuesday include:

• A CBS News-New York Times poll of likely voters showed Obama with 53 percent support and McCain with 39 percent.