SAYNER, Wis. — Wisconsin voters go to the polls on Tuesday to decide whether to remove six Republican state senators, more recall election efforts of state legislators in a single day than have ever taken place in Wisconsin and the latest chapter in what has been one of the most polarized, vitriolic political years in memory.

The recall campaigns — against six Republicans on Tuesday and against two Democratic state senators next week — have drawn frenetic get-out-the-vote efforts by local and national groups that have set up camp in affected cities and towns, filled radio and television airwaves across the state (and even into Minnesota) and led to what is expected to be some $30 million in spending by campaigns and outside groups, placing some of these among the costliest state legislative races ever to take place here.

“This is off the charts for Wisconsin, wildly off the charts,” said Mike McCabe, the executive director of the Wisconsin Democracy Campaign, which has tracked the spending and says it has come from numerous sources, including union groups that want to see the Republicans removed and, on the other side, conservative groups like the Club for Growth Wisconsin and Americans for Prosperity. “This gives whole new meaning to the word ‘unprecedented.’ ”

These elections, oddly timed during the state’s sleepy vacation season, were fueled by the anger that has split the state since Gov. Scott Walker, a Republican, and Republican lawmakers took over control of the government this year, and pursued an aggressive agenda — in particular, cutting collective bargaining rights for public workers as a way, they said, to solve the state’s budget gap. At stake on Tuesday is dominance of the State Senate; Democrats would need to win three seats to grab the majority and slow Mr. Walker’s ability to set the state’s direction.