DES MOINES – Democratic Sen. Barack Obama is launching two biographical television ads this week, focusing on early voting Iowa in the first commercials of his presidential campaign.

The ads represent a strategic shift for the Obama campaign, which has focused on grass-roots efforts and now will introduce the candidate to a new population of voters watching at home.

Candidates typically hold off on advertising during the slow summer months, but the warp-speed campaign has forced the 2008 contenders to rethink the traditional approach. Republican Mitt Romney and Democrat Bill Richardson have run ads in Iowa and seen their poll numbers increase.

Obama’s two spots are just the start of what could be an unprecedented campaign on television. The Illinois senator has millions of dollars to spend on advertising along with other campaign activities.

Obama aides planned a conference call Monday to discuss the new commercials, featuring a Republican lawmaker who worked with Obama in the Illinois State Legislature and Harvard Law professor Laurence Tribe.

Both Tribe and Republican Sen. Kirk Dillard are featured in the new commercials. The spots also feature scenes of Obama speaking at the 2004 Democratic National Convention, which vaulted him to prominence within the party.

A 60-second commercial called “Choices” focuses on the decision Obama made after graduating from Harvard Law School, opting to turn down lucrative offers from law firms and instead move to Chicago as a community organizer.

The 30-second spot, “Carry,” addresses Obama’s work in the Illinois Legislature, where Dillard praises him for pushing ethics legislation, expanding child care and health coverage and supporting tax credits for the working poor.

“Senator Obama worked on some of the deepest issues we had and was successful in a bipartisan way,” Dillard says in that ad.

Aides described Tribe, a member of the Harvard law faculty, as a mentor for Obama. Tribe praises Obama for his decisions after graduating.

“It was inspiring, absolutely inspiring to see someone as brilliant as Barack Obama, as successful, someone who could have written his ticket on Wall Street, take all of the talent and all of the learning and decide to devote it to the community and to make people’s lives better,” Tribe says in the commercial.

The Obama campaign is spending a modest amount of money to run his first ads in Iowa.

A recent poll in Iowa showed Obama bunched at the top with rivals Hillary Rodham Clinton and John Edwards. His appearances in the state have drawn large and noisy crowds.

The ads come soon after an extensive mailing, which included a DVD biographical film on Obama, aides said.

By airing the ads, Obama likely is hoping to increase poll numbers that have stalled somewhat since he entered the race with great fanfare, said Bruce Gronbeck, a University of Iowa political science professor who specializes in political advertising.

“Obama may feel like he has stalled a little but and needs something of a push,” Gronbeck said