John Kerry (search), seeking to shift the presidential campaign focus to the economy, pledges to "stand up for the middle class" and suggests President Bush (search) "sides with the special interests" in new ads that are part of a $50 million post-Labor Day blitz starting in seven key states.

Kerry's commercials begin airing Friday in Ohio, then next week in Florida, Iowa, New Mexico, Pennsylvania, New Hampshire and Wisconsin, according to Democratic officials familiar with the two-months-long buy.

"President Bush insists the economy is just fine. We know America can do better," Kerry says in one ad tailored to Ohio.

The campaign also was reserving air time in an additional 13 states that will create a coast-to-coast battleground map by Nov. 2. The rest of the states — Minnesota, Missouri, Nevada, Oregon, Washington, Maine, Michigan, Arizona, Louisiana, Colorado, Arkansas and North Carolina and West Virginia — won't see the spots until later this fall.

Ads will air on local network affiliates, cable TV and broadcast outlets targeting minorities.

The new commercials highlight the economy as the Kerry campaign seeks to move the focus of the race from questions about the Massachusetts senator's decorated Vietnam service and subsequent anti-war activities some 30 years ago.

By comparing his own domestic proposals with his views of the country under the Bush administration, Kerry attempts to make a case for change, not an easy task for a presidential challenger in a time of war.

In one spot emphasizing his health care and jobs proposals, Kerry says: "The fundamental choice in this election is between a president who will fight for the middle class and a president who sides with the special interests in this country."

"I'll be a president who will stand up for the middle class," Kerry pledges in the ad, which will start running Tuesday on national cable networks.

In another ad specific to Ohio, Kerry notes the state was "hit hard" by the economic downturn. "In the past four years," Kerry says, "Ohio has lost 230,000 jobs. President Bush insists the economy is just fine." Then, Kerry promises to bring "good wages, good benefits, a plan for the heartland."

Bush, in New York for his nominating convention, was placing his first fall ad order this week, with ads slated to begin airing Tuesday. Unlike Kerry's lengthy purchase, Bush's buy is expected cover one or two weeks at a time.

Kerry's $50 million blitz is more than half of the roughly $90 million the Democrat has at his disposal between now and Election Day. Campaign officials also said Kerry has budgeted an undisclosed amount of money to pour into key states later in the fall.

There are no surprises among the 20 states that Kerry has effectively identified as his battlegrounds. The remaining 30 states plus the District of Columbia are considered either safely Republican or Democratic, with the possible exception of Virginia.

Of Kerry's top seven states, four were narrowly won by Democrat Al Gore in 2000: Iowa, Wisconsin, New Mexico and Pennsylvania. Three other states were barely won by Bush, including Florida, where he won with a 537-vote margin.

To reach the 270 electoral votes needed to win the presidency, Kerry needs to reclaim each of the states won by Gore plus pick up 10 electoral votes. His biggest targets are economically ailing Ohio (20 votes) and Florida (27 votes), where the Democratic-leaning population is growing. Bush also won New Hampshire and its four electoral votes.

Of the 13 states slated for ads in later waves, Nevada and West Virginia, with a combined 10 electoral votes, are considered to be Kerry's best opportunities to claim a state won by Bush four years ago.

Nevada has a growing Hispanic population, and many voters there fault Bush for his support of a nuclear waste site in the state. West Virginia is filled with cultural conservatives courted by the GOP, but a tough economy and the Iraq war could help Kerry.

Officials said the fall commercials will focus on local media markets with the heaviest numbers of undecided, independent or persuadable votes. Eventually, they may begin airing in heavily Republican or Democratic areas as Kerry searches for the stray swing voter, aides said.

In Virginia, Kerry has spent $2.5 million to try to make the state competitive, but it didn't make the list.