DES MOINES, Iowa — Senator Clinton unveiled the first television ad of her presidential campaign yesterday, a commercial set to air in Iowa where she is in a tight race with rivals Senator Obama and John Edwards.

The 60-second spot, which goes up today on Iowa television, intercuts scenes of Mrs. Clinton interacting with voters and delivering a portion of her standard campaign speech in which she speaks of the challenges facing many working people.

“If you’re a family that is struggling, and you don’t have health care, you are invisible to this president,” she says. “If you’re a single mom trying to find affordable child care so you can go to work, you’re invisible, too.

“Americans from all walks of life across our country may be invisible to this president, but they’re not invisible to me, and they won’t be invisible to the next president of the United States,” she says to applause. A former Iowa governor, Tom Vilsack, who endorsed Mrs. Clinton’s bid for the Democratic nomination after dropping out of the 2008 race, planned to unveil the new commercials at a news conference.

The move intensifies Mrs. Clinton’s campaign in Iowa, her weakest state, and comes on the eve of her latest campaign swing here. Iowa is slated to hold its caucuses on January 14, though the date is certain to change after South Carolina Republicans moved up their primary last week.

Some state polls show Mr. Edwards leading while others show Mrs. Clinton and Messrs. Obama and Edwards essentially tied.