SIOUX CITY -- Former Iowa first lady Christie Vilsack will enter the Iowa 4th District congressional race Tuesday.

Late Friday, a prominent Democratic Party source with knowledge of Vilsack's plans told the Journal that she will announce her candidacy on Tuesday. The decision will likely set off one of the most contentious and expensive congressional campaigns of the 2012 election cycle.

Woodbury County Democratic Party Chairman Dave Somsky confirmed Vilsack will visit Western Iowa Tech Community College in Sioux City on Tuesday for a major campaign announcement. She is also expected to make appearances elsewhere in the district.

"I would expect her to run, with all the work and time she's put into it," Somsky said.

The news comes on the heels of Thursday's announcement that Vilsack's exploratory congressional campaign had raised $424,339 in the quarter since April. Ann Trimble-Ray, campaign spokesman for incumbent Republican Steve King, said Friday that the congressman would have no comment on the candidacy of Vilsack or her fundraising efforts.

King started the April quarter with a little more than $142,000 on hand. King's fundraising report for the most recent quarter was not available by the Journal's press time.

Vilsack moved to Ames, one of the southeast-most counties of the newly redrawn 4th Congressional District, earlier this year. She also stopped in Sioux City, Storm Lake and many other cities in the late spring as part of a so-called listening tour while mulling a congressional bid.

King currently represents the 5th District, but his Kiron home lies within the new 4th District.

King easily won five previous elections in the 5th District, the Iowa congressional seat with the highest Republican voter registration. He defeated Paul Shomshor in 2002, Joyce Schulte in 2004 and 2006, Rob Hubler in 2008 and Matt Campbell in 2010.

Several Northwest Iowa Democrats said they saw Thursday's fundraising announcement as the precursor to her official announcement.

Former Woodbury County Democratic Party Chairman Al Sturgeon of Sioux City said he embraces the quest by Vilsack, who was praised for her political instincts when campaigning on behalf of her husband, former Iowa governor and current U.S. Secretary of Agriculture Tom Vilsack. Tom Vilsack won gubernatorial campaigns in 1998 and 2002.

"She has two things going for her that we've never had before in a congressional candidate. No. 1, name recognition, and secondly, early money," Sturgeon said. "In fact, most of our candidates haven't had much money."

When former Monona County Democratic Party Chairman Ken Mertes of Onawa heard Vilsack speak during the listening tour, he noted she was "careful to craft her words." But Mertes said he always expected she would run against King.

Dave Bernstein, a Sioux City businessman and Democratic activist, said Vilsack is a candidate Northwest Iowa Democrats will rally behind.

"She is very clearly in touch with Iowa, both small- and large-town Iowa, from her roots and her past experience. I just think that Steve is out of touch with a lot of what goes on in Iowa, in our district and in our new district," Bernstein said.

"She had an extremely strong last quarter of fundraising that puts her at a level far and beyond anybody else who has run against Steve King. I think that is huge, because in the day and age where, unfortunately or fortunately, money is part of the equation in running a political campaign, if she runs, she will be a very well-financed candidate."