DES MOINES — The three leading Democrats are making their closing pitches to Iowa voters in televised appeals on the eve of the state’s caucuses.

Senator Clinton is asking Iowans to “take the first step” toward changing the direction of the country by voting for her at the caucuses.

“After all the town meetings, the pie and coffee, it all comes down to this: Who is ready to be president and ready to start solving the big challenges we face on Day One,” Mrs. Clinton says in the two-minute appeal to be broadcast during today’s evening news programs.

John Edwards will rely on the words of a laid-off Maytag worker, Doug Bishop, who offers a one-minute testimonial that recalls Mr. Edwards’s pledge to Mr. Bishop’s son four years ago that “I’m going to keep fighting for your daddy’s job, I promise you that.”

Senator Obama, like Mrs. Clinton, purchased two-minute time slots across the state, for an ad that will air during news broadcasts. Also, in an e-mail to Iowa supporters yesterday, an Obama state director, Paul Tewes, cast the Illinois senator as the Democratic candidate who can attract independents and Republicans. The campaign did not immediately make a copy of the TV ad available.

In Mrs. Clinton’s ad, the New York senator recounts her months of stumping through Iowa, saying “the stories you have shared will always stay with me.” Iowa, first among the states to vote on nominees for president, holds its caucuses tomorrow night.

“I know you have waited a long time for a president who could hear you and see you,” Mrs. Clinton says. “I would like to be that president. So I ask you to caucus for me tomorrow. Put on your coats and call up a friend and help me change America.”

Mrs. Clinton talks directly to the camera as she summarizes her bid, arguing as she has on the stump that she alone has the experience — eight years as first lady and seven years in the Senate — to take command of the White House quickly.

Simple and spare in production, her campaign tries to create the aura of an Oval Office address with the ad. In a close-up shot, Mrs. Clinton is seated with what appears to be a window and table topped with flowers in a vase in the background.

“I’m not running for president to put Band-Aids on our problems. I’m running to solve them,” she said, as she has many times at campaign events.

Mrs. Clinton adds a human touch to deflect criticism suggesting she is cold and calculating.

“You have welcomed me into your hearts and your homes. And I thank you,” she says. “Parents juggling jobs to pay for college for their kids. Soldiers’ families praying for a safe return. All the men and women across the state who have whispered their health care problems to me — bills they can’t pay, parents they can’t afford to care for, insurance companies who refuse to help.”

Most surveys show Mrs. Clinton, Mr. Obama, and Mr. Edwards in a close and fluid three-way contest. Those surveys also have identified a large group of activists who have yet to settle on a candidate or who say they could still change their minds.

Mr. Edwards makes his last appeal to Iowa voters, not with his own words, but those of Mr. Bishop, a working class father. By using Maytag as a foil, the ad touches an emotional nerve in Iowa. Maytag’s washer and dryer factory was once the pride of Newton, Iowa, until it closed its doors in October. For Mr. Edwards, the plant represents a symbol for his populist rhetoric — one that criticizes corporations, foreign trade deals, and special interests.

“I want a guy that’s going to sit down and look a 7-year-old kid in the eye and tell him, ‘I’m going to fight for your dad’s job,'” Mr. Bishop says, as he introduces Mr. Edwards to an Iowa crowd. “That’s what I want. I’m going to do my best to make sure that my children aren’t the first generation of Americans that I can’t look them in the eye and say, ‘You’re going to have a better life than I had.'”

Mr. Edwards supplemented his television spot with a full-page ad in the Des Moines Register that included a written message from Mr. Bishop and a lengthy essay from Mr. Edwards.