Recall fatigue may be setting in for Wisconsin voters. But when another cluster of them heads to the polling booths Tuesday, their votes not only could have a significant impact on the Wisconsin Senate, but also could provide a glimpse a what might transpire nationwide in 2012.

In Tuesday's recall elections, two Democratic incumbents in the state Senate face Republican challenges. Last week, six Republican state senators faced recalls, with four holding on to their seats. That leaves Republicans with a 17-16 advantage in the state Senate.

While Republicans cannot lose their majority Tuesday – meaning they will retain control of the Senate, Assembly, and governorship – picking up an extra seat could give them valuable legislative breathing room.

If both Democrats prevail, however, the election could offer further evidence that the country's broad political middle is swinging back left after the tea party triumphs of last November. The composition of Wisconsin's electorate almost exactly matches America's, polls suggest, meaning that the state is emerging as a microcosm of the national political mood, which makes it a crucial bellwether in the 2012 national election.

Fundamentally, Wisconsin is a purple state – neither red nor blue – "and that makes it important,” says John McAdams, a political scientist at Marquette University in Milwaukee.

Even with Republicans ruling all three branches of state government no matter the outcome, Tuesday’s election does give Democrats a chance to hold tight to that slim margin, which they can use to strategize with Republican moderates to vote against future conservative legislative efforts.

“A one-vote majority in any legislative assembly is pretty tenuous,” says Professor McAdams. “Republicans would really be quite better off if they could pick up one of the races on the ballot.”

Tuesday’s recall elections pit Democratic Sen. Bob Wirch against challenger Jonathan Steitz, a corporate attorney, in the Kenosha-area 22nd Senate District. In the other race, Democratic Sen. Jim Holperin is being challenged by Kim Simac, a tea party activist, in the 12th Senate District, located in the north.

The campaigns can’t help but address the controversial legislation pushed by Gov. Scott Walker (R), which includes bills to limit the collective bargaining of unions, give gun owners the right to carry concealed weapons, redistrict political boundary lines, and create tougher ID restrictions at the voting booth.

But with Democrats in the hot seat this week, the debate is also focusing on Democratic senators' out-of-state exodus in February to stall voting on Governor Walker’s collective-bargaining bill – an action that Mr. Steitz is calling “a dereliction of duty.”

“I can understand if they were gone for a few days, but they were away three weeks. We can’t run government like that,” he told an ABC affiliate in Milwaukee Sunday.

On the same program, Senator Wirch defended the temporary move to Illinois, saying he and his fellow 13 senators never expected to stop the Walker agenda. They were “simply trying to educate the public by drawing out the process,” he said.

Walker was criticized at the time for trying to push through the bill in three days with scant public input, an action he has recently suggested he regrets.

The Holperin race is being viewed as more competitive than the Wirch race, based on spending. To date, the Holperin race has generated $4.5 million for both sides, more than double than the $2.3 million spent in the Wirch race, according to the Wisconsin Democracy Campaign, a Madison-based watchdog group that tracks election spending.

So far, both Democrats have double-digit leads over their challengers in most polls. For example, Senator Holperin is leading Ms. Simac, 55 to 41 percent, and Wirch leads Steitz, 55 to 42 percent, according to a poll by Public Policy Polling, a Raleigh, N.C., polling firm that often works for Democrats.

Another poll, by We Ask America, a conservative leaning polling firm in Springfield, Ill., reports Holperin leading Simac, 51 to 49 percent. The organization did not have polling results for the Wirch race.

If Tuesday produces a win for both Democrats, Wisconsin will tilt further toward the color purple, as opposed to red, the result of the November 2010 midterm elections, which swept a large majority of Republicans into each legislative branch.

A Gallup poll released last week reports that 45 percent of Wisconsinites say they are Democrats and 40 percent say they are Republicans, a finding that is nearly identical to the national result in the same poll. Voting was based on a random sample of 177,600 adults in all 50 states.

With the electorate split roughly down the middle, Wisconsin is a state that political scientists are watching closely.

Even though state voters easily handed a win to Barack Obama in 2008, it wasn’t the case for Democratic challengers in the 2000 or 2004 presidential election cycles, who eked out narrow victories over George W. Bush in the state. With the recent midterm elections going to Republicans, McAdams says the stage is set for another swing toward the left.