Tomorrow is Primary Day in Illinois.

In the Senate primary, the best-known candidate on the Democratic side is state treasurer Alexi Giannoulias of Chicago; he’s expected to win pretty easily against Chicago inspector general David Hoffman, Chicago Urban League president Cheryle Robinson Jackson, and three other lesser-known candidates.

On the Republican side, Rep. Mark Kirk is the favorite, going up against lawyer Patrick Hughes, Alderman John Arrington, former circuit-court judge Don Lowery, lawyer Andy Martin, and former school-board member Kathleen Thomas.

As I said last week, Hughes has broken out of the pack, for whatever that’s worth, but still trails Kirk by a hefty margin.

Is Kirk too liberal for a conservative to vote for in good conscience? His lifetime ACU rating is a pretty “meh” 55.69. He voted for the cap-and-trade legislation. He’s worked with Mike Bloomberg on some gun-control measures. (Grumblegrumblegrumble.) He said that if he were John McCain, he wouldn’t have picked Sarah Palin as his running mate. (Grumblegrumblegrumble.)

Having said that, he’s a Republican who’s managed to win repeatedly in a pretty Democratic district (Cook PVI: D+6) and survived in a year when Obama carried 61 percent of the vote in his district. Even though he looks young enough to get carded at most bars, he’s a commander in the Naval reserves, and in late 2008 he traveled with the Navy as a special adviser for counternarcotics, making him, according to Michael Barone’s Almanac of American Politics the first House member since World War II to serve in a combat area. He supported the surge, opposed withdrawal from Iraq in 2008. He’s got a lifetime rating of 86 from the U.S. Chamber of Commerce. If Kirk becomes a senator, he seems likely to please foreign policy and fiscal conservatives, while disappointing social conservatives.

There’s not a ton of polling in the potential matchups, but right now, Kirk trails in the most recent one; earlier polls had it tied or a small lead for Kirk. If a Republican can win in Massachusetts, there’s no reason the GOP shouldn’t have a shot in Illinois in the post-Blago era.

In their gubernatorial race, Democratic incumbent Pat Quinn, the man who took the place of Rod Blagojevich, is running for a full term and is in trouble against state comptroller Dan Hynes.

A small army of candidates has massed on the Republican side: entrepreneur Adam Andrzejewski, state senator Bill Brady, state senator Kirk Dillard, Illinois Republican party chairman Andy McKenna, small businessman and radio commentator Dan Proft, and former state attorney general Jim Ryan. Polling suggests this a close race, and with six candidates all within a few percentage points of each other, it’s anybody’s game.

Andrew Andrzejewski certainly is turning heads in the final days; you can’t find many better endorsers in a GOP primary than Lech Walesa (yeah, that Lech Walesa) and Eduardo Verastegui, actor and pro-life activist. That campaign says their internal polls show them surging. Of course, in a six way race, a few points might count as a surge – and be enough for a win.