Illinois voters are expected to flock to the polls in today’s primary, which features not only home-state presidential candidate Sen. Barack Obama (D-Ill.) on the ballot, but a handful of potentially close races in the nation’s first Congressional nominating contests of the year.

In the state’s 14th Congressional district, voters also will cast their votes for a March 5 special election to complete the term of recently retired former Speaker Dennis Hastert (R).

Hastert’s official announcement in December kick-started a multi- million-dollar open-seat contest featuring Republican dairy magnate Jim Oberweis and state Sen. Chris Lauzen (R), a matchup that has become tense during the past two months.

Hastert, whose retirement was widely rumored from the outset of the 110th Congress, announced in mid-October that he was retiring, but declined to say when. After stalling for weeks, a tactic designed to avoid holding the primary and special primary elections on separate days,

Hastert officially stepped down in a letter to Gov. Rod Blagojevich (D) on Nov. 26.

Within weeks, Hastert endorsed Oberweis, a wealthy self-financier who has spent more than $6 million since 2002 on two doomed Senate bids and one gubernatorial bid in which he failed to make the November ballot. Hastert’s endorsement, considered half-hearted by some state political insiders, was unsurprising given the long-term political friction between establishment outsider Lauzen and the former Speaker.

In addition to Hastert’s nod, Oberweis has been endorsed by Illinois GOP Reps. Ray LaHood and Timothy Johnson, House Chief Deputy Minority Whip Eric Cantor (Va.), Republican Conference Chairman Adam Putnam (Fla.) and former National Republican Congressional Committee Chairman Tom Reynolds (N.Y.).

Oberweis’ campaign has taken in more than $2 million this cycle, primarily out of the candidate’s own pocket. He had spent roughly $1.7 million as of Jan. 16, according to the Federal Election Commission.

Lauzen, an accountant, had raised about $1.1 million through Jan. 16 and owed his campaign roughly $325,000.

A survey conducted for Oberweis’ campaign in late December showed that Oberweis had a 12-point lead in the race, a sharp increase over an October poll taken for his campaign.

On the Democratic side, wealthy self-funding physicist and Democratic Congressional Campaign Committee favorite Bill Foster is expected to beat union carpenter John Laesch and a handful of other long-shot Democrats today. Assuming Oberweis and Foster are the nominees, that would set up a contest of freely spending millionaires in the special election — which could then be repeated in November.

Hastert’s former district, made up of exurban counties west of Chicago and a patch doglegging south toward the Mississippi River, gave President Bush 55 percent of the vote in 2004 and 54 percent in 2000, but Democrats believe the district is trending in their direction.

In Chicago’s posh North Shore suburbs, business consultant Dan Seals (D) is doing battle with former Clinton White House official Jay Footlik (D), a district native whose unlikely victory would hinge on carrying the substantial local Jewish population. Seals, a black political novice who was not supported by the Democratic Congressional Campaign Committee when he ran for Congress the first time in 2006, lost to incumbent Rep. Mark Kirk (R) last cycle by fewer than 15,000 votes.

Kirk, who has raised more than $2.3 million this cycle, is unopposed in the Republican primary, but will be a heavy DCCC target regardless of who emerges from today’s primary.

Seals had raised roughly $900,000 this cycle through Jan. 16, compared with Footlik’s $614,000 haul. Seals had about $627,000 in the bank; Footlik had $133,000.

Seals has been endorsed by Sen. Dick Durbin (D-Ill.), area Rep. Jan Schakowsky (D), House Majority Whip James Clyburn (D-S.C.) and the Windy City’s two metropolitan newspapers, the Chicago Tribune and the Chicago Sun-Times. Footlik has been endorsed by the Illinois Federation of Teachers and the suburban Lake County News-Sun.

Two-term Rep. Dan Lipinski (D-Ill.) will face anti-Democratic machine activist Mark Pera, an attorney who has outraised the incumbent this cycle and attracted considerable attention from local politicians and party activists.

Lipinski, the son of former Rep. Bill Lipinski (D-Ill.) who hand-delivered the seat to his son in 2004, seems undeterred by his challenger, who has spent roughly $540,000 of the nearly $615,000 he’s raised to unseat Lipinski. Through Jan. 16, the incumbent had spent $191,000 of the $465,000 he’s raised this cycle.

Democrats capitalized early last fall following ethics-clouded Rep. Jerry Weller’s (R-Ill.) decision to retire, clearing the field for state Senate Majority Leader and DCCC recruit Debbie Halvorson (D).

New Lenox Mayor Tim Baldermann is expected to carry today’s Republican primary vote, a contest that also includes long-shots Terry Heenan and Jimmy Lee. Baldermann has proved himself a reluctant fundraiser so far this cycle, bringing in little more than $100,000 and spending about half.

“I have done very little fundraising,” Baldermann told a local newspaper last month. “It makes me sick to my stomach. My campaign people gave me a list of people who gave money to [Weller]. I told them, ‘If you think I’m going to call somebody who’s never heard of me and ask for $2,300, that’s insane.’ I fight with them every single day over it.”

Halvorson had $394,000 in cash on hand going into today’s primary, according to her Jan. 16 FEC filing.

In retiring Rep. Ray LaHood’s (R) central Illinois district, which takes in parts of capital city Springfield, state Rep. Aaron Schock, a GOP wunderkind, faces former local politician John Morris and businessman Jim McConoughey in the primary.

As of Jan. 16, Schock, who is only 26, had spent roughly $520,000 of the $800,000 he had raised. McConoughey had spent about $250,000 of the $296,000 he had raised though the last filing deadline, while Morris spent about $325,000 of the $410,000 he had raised.

Although the district could be competitive on paper, it is not clear whom the Democrats will nominate — and the nomination will not be settled today.

Dick Versace (D), a former college and professional basketball coach, was heavily recruited by the DCCC to run in the open-seat contest to replace LaHood. After raising a respectable $400,000 in the first few months of his campaign, Versace — who was running unopposed — unexpectedly dropped out of the race late last year for undisclosed reasons.

Under a law enacted late last year, Democratic leaders may be able to field another candidate for the House seat.