By WILLIAM PETROSKI

U.S. Sen. Tom Harkin, the senior Democrat in Iowa's congressional delegation, today endorsed incumbent U.S. Rep. Leonard Boswell in his party's June 3 primary battle for the 3rd District nomination.

Former state legislator Ed Fallon of Des Moines has scheduled a news conference today to officially launch his campaign to oppose Boswell for the Democratic congressional nomination, contending Boswell has voted too often with President Bush.

Fallon is a maverick who has been willing to buck his party's leadership in past. During the 2000 presidential campaign, he angered Democratic officials by endorsing Green Party nominee Ralph Nader over Democrat Al Gore.

Harkin issued a statement in support of the 74-year-old Boswell, who has said he plans a vigorous campaign to retain his seat.

"Congressman Boswell has a record of delivering for Iowa," Harkin said. "He has fought tirelessly to strengthen our schools, expand access to health care, and rebuild our roads. As a decorated veteran himself, he has given a voice to the brave men and women who has served our country and has devoted himself to ensuring they are provided for. As a tried and true fighter, Boswell has fought off tough Republican opponents in the past and will win again this November."

The 3rd Congressional District covers the counties of Polk, Jasper, Marion, Lucas, Monroe, Mahaska, Keokuk., Poweshiek, Iowa, Tama, Benton and Grundy.

Fallon, 49, who served 14 years in the Iowa House, said he will campaign on issues that include global warming, universal health care, campaign finance reform, poverty and fiscal responsibility. He favors freedom of choice on abortion and has opposed efforts to outlaw gay marriage.

"While Leonard Boswell is an honorable man who has served proudly and with dignity, I feel his positions on key issues are wrong," Fallon said. "I'm ready to take on corporate interests who have corrupted our federal government. I'm ready to give working families and the poor a voice in national politics. I'm ready to apply what I've learned during 23 years of public service and be part of the solution in Washington."

Two years ago, Fallon ran in the Democratic primary for governor, receiving 26 percent of the vote. He believes he has a chance to unseat Boswell because he defeated his main Democratic rivals for governor -- Chet Culver and Mike Blouin -- in the 3rd District primary.

Fallon said his campaign has 13 full-time employees and is building a field operation. Fallon has said he has raised about $60,000 in campaign money, while recent federal election records showed Boswell with about $600,000 in cash.

Boswell issued a statement today defending his candidacy.

"I'll put my work ethic and record standing up for everyday working families up against anyone. Whether it's improving health care for women and children; expanding educational opportunities; promoting a modern day energy policy that creates jobs for Iowans; and making sure our returning veterans receive the care they deserve -- I will continue to take a common sense approach to solving problems and challenges we face together," Boswell said.

"I've always believed that elections were about bringing people together to improve the lives of working families. Now, more than ever, we need to focus our energy on solving problems -- not trying to tear each other apart," Boswell added.

No Republicans have announced their candidacy for the 3rd District race, but about a dozen Republicans are mulling a possible bid, said Chuck Laudner, executive director of the Iowa Republican Party. He said he doesn't expect former state Sen. Jeff Lamberti of Ankeny to run again this year after a strong race as the Republican candidate in 2006.

Steve Roberts of Des Moines, a Republican National Committee member, said it's difficult to unseat a veteran incumbent such as Boswell, who has served 11 years in Congress. But if Fallon were to upset Boswell, he would expect a groundswell of interest among Republicans in trying to capture the congressional seat.