Updated at 10:41 a.m. ET

Remember the protests in Wisconsin earlier this year over Gov. Scott Walker's budget proposal to end collective bargaining for public employees?

Voters on Tuesday will go to the polls to keep or boot out six Republican state senators, in a recall election that could have serious implications for the 2012 campaign. Next week, two Democratic senators face voters.

Democrats need to win three seats to win control of Wisconsin's state Senate.

About $30 million is being spent to influence voters, according to Mike McCabe of the non-partisan Wisconsin Democracy Campaign. McCabe told ABC News that $25 million of that is from outside groups on both sides of the recall election and the rest is from the Senate candidates.

McCabe told Mother Jones that by comparison $3.75 million was spent on state races in 2010.

Recall spending "is totally off the charts," McCabe is quoted as saying in Mother Jones. "This is so out of whack from everything we've seen."

The liberal groups, Progressive Change Campaign Committee (PCCC) and Democracy for America, are spending $2 million in Wisconsin on a TV ad campaign and a grassroots effort to get out the vote.

The ad features Eric Christiansen of Whitefish Bay, Wis., a teacher who says he's voted Republican in the past for Ronald Reagan, both of the Bush presidents and state Sen. Alberta Darling, one of the recall targets.

Christiansen says he's voting for Darling's opponent, Sandy Pasch, because the Republican voted for budget cuts that hurt the state schools.

"Even Republican voters are turned off by the Republican Party's war on middle-class families -- a war that's taking place from Wisconsin to the halls of Congress," said Stephanie Taylor, co-founder of the Progressive Change Campaign Committee. "Wisconsin Democrats are showing the nation what it looks like to fight back and win. This victory will make the history books."