Not only are Wisconsin Republicans thrilled at the prospect of unseating 18-year incumbent Sen. Russ Feingold (D) this cycle, they are also hoping to achieve the biggest statewide GOP shift in the country, at every level of government.

Democrats currently control just about every aspect of Wisconsin politics — the governorship, both houses of the state legislature, five out of eight House seats, and both Senate seats. Not for long.

Slim Democratic majorities in the State Senate (18 D, 15 R) and State Assembly (50 D, 45 R) are widely expected to flip to the Republicans, propelled by the larger GOP wave and strong candidates at the top of the ticket.

Scott Walker (R) should win comfortably over Tom Barrett (D) in the gubernatorial race. In fact, Barrett never really had a shot. Walker has consistently maintained a lead of about 7-8 points (on average) since polling began in January.

As has Ron Johnson, the “jewel in the crown” of the state GOP (and perhaps the Tea Party writ large) this year. At this point it seems the question is not if Johnson can send Feingold packing, but by how much? Some polls have had the Republican up double digits; a blowout win would send a powerful message. Johnson will no doubt pull a number of down-ticket candidates across the finish line with him.

As for the House, the GOP has a very good opportunity to pick up three Democratic seats, and is in no danger of losing any Republican-held seats. Former MTV Real World star and lumberjack aficionado Sean Duffy (R) looks well-positioned to defeat Julie Lassa (D) in the race for Rep. Dave Obey’s seat in the 7th District. Likewise, Reid Ribble should unseat Rep. Steve “I’m writing the health-care bill” Kagen (D) in the 8th district. Rep. Ron Kind (D) looks slightly more secure in the 3rd district against Republican Dan Kapanke, though he will have to get lucky to survive this wave. Our own Jim Geraghty is predicting a Kapanke win, and BATTLE ‘10 concurs.

Expect to see six Republicans in the House delegation Wisconsin sends to the 112th Congress, leaving Democrats with representatives from the 2nd District — which includes Madison, a.k.a. the “Berkley of the Midwest” — and the 4th district — in downtown Milwaukee, which voted 75 percent for Obama — seats Republicans could hardly ever hope to win. That said, Kenneth R. Mayer, professor of political science at the University of Wisconsin-Madison, tells BATTLE ‘10 that Rep. Tammy Baldwin (D., WI-02) has been running ads in Madison against her opponent, 27-year-old businessman Chad Lee (R). Merely an “”insurance policy” to be sure, Mayer says, but almost unprecedented in a district that voted nearly 70 percent for Obama.

For Democrats, “this must feel like a trainwreck,” Mayer says. Indeed. Such a big shift in Wisconsin this cycle could have significant implications for 2012. The state has voted Democratic in the last six presidential contests and went 56 percent for Obama in 2008, but could be on the verge of turning red. It certainly will be after tonight.