Updated

Television advertising by President Bush and Sen. John Kerry (search) and their political parties is focused on 14 states, reflecting a shrunken battleground in the final month of the presidential campaign.

Republican Bush's campaign has scaled back its ads in Democratic-leaning Washington in recent weeks and it is pulling out of Missouri, where polls show the president leading, since Kerry and the Democratic Party are no longer on the air there. The Democrat, meanwhile, abandoned plans to return to the air this week in North Carolina, historically a Republican state.

Both sides are saturating airwaves in 14 other states, according to an Associated Press analysis of airtime bought over the past week by Bush and the Republican National Committee (search) and Kerry and the Democratic National Committee (search).

The most ads are running in Florida, Ohio, Pennsylvania and West Virginia. However, 10 other states — Colorado, Iowa, Maine, Michigan, Minnesota, Nevada, New Hampshire, New Mexico, Oregon, Wisconsin — also are seeing heavy advertising.

Based on a review of the country's 210 media markets, an independent analysis found that the top 50 markets for political ads reach only 27 percent of the electorate. The analysis by Nielsen Monitor-Plus and The University of Wisconsin Advertising Project was released Tuesday.

Political ads reach a national audience through cable television, but the majority of candidate and party advertising in the presidential election has been on local TV stations in states the campaigns deem competitive.

Three weeks before the Nov. 2 election, strategists in both camps are trying to determine where they must win to get the 270 electoral votes needed to claim the White House, and they're adjusting spending accordingly.

In spring and summer, Kerry's campaign had advertised in local media markets in 21 states. It spent millions as it looked to expand the battleground by trying to put GOP-leaning states like Virginia, Louisiana, Arizona and Arkansas in play. The attempt failed and no ads are running in those states.

The same goes for GOP-leaning North Carolina, home to Kerry running mate John Edwards. Kerry's campaign advertised there after naming Edwards to the ticket, but pulled the plug on plans to return to the air there Tuesday.

This fall, Kerry's campaign and the Democratic Party also pulled its ads from Missouri. While long considered a swing state, Missouri has been trending Republican and Bush has a substantial lead in polls there.

At the same time, Bush's campaign is pulling its ads in Missouri this week, and it is running only a trickle of ads in Washington state, which Democrat Al Gore won by 5.6 percentage points in 2000. Bush ads were on the air in Washington at heavy levels last month.

That leaves 14 states still in play.

Last week, Bush and his party spent about $15 million on advertising, compared with about $17 million for Kerry and his party. The Democrats are slated to spend about the same amount this week; Republicans have bought about $12 million worth of TV and radio airtime for the week.

Since their party conventions, Kerry and the DNC, including the party's independent advertising operation, have spent about $80 million on advertising compared with about $70 million for Bush and the RNC. That doesn't include the $200 million or so both sides combined spent during the spring and summer.

At the same time, interest groups continue to pour money into the race.

The United Auto Workers' political action committee launched $2 million worth of radio and TV ads in eight states this week. The commercials criticize Bush on jobs and health care and claim Kerry will fight for working families.

The November Fund, a group of Republican insiders partly funded by the U.S. Chamber of Commerce, is running TV ads assailing trial lawyers in a handful of states. The ads are supposed to attack Edwards, a former trial lawyer. However, by law, they can't name him or the presidential race because they are paid for in part with corporate money.

Hollywood director Rob Reiner also has made a TV ad for MoveOn.org's political action committee in which he says: "Four years ago, a mistake was made. On November 2, we can correct that." The ad will run on national cable networks.