DINESH RAMDERACINE, Wis. (AP) â¿¿ Al Trossen feels like a wanted man. The former Teamster voted for embattled Wisconsin Gov. Scott Walker in 2010 but isn't sure who to support in the state's historic recall election next month. "There's so much bashing on both sides," the 71-year-old retired truck driver said. "How does a person know what to believe?" A few days before a Democratic primary that will decide who will take on the Republican Walker, and four weeks until the general election, it's not easy to find undecided voters like Trossen. One recent poll put the percentage of undecided voters in the low single digits. But that tiny group will be the focus of extraordinary attention now in a fiercely fought campaign that has become a national battle over worker rights. With the race a virtual toss-up, the rival forces â¿¿ which include the national Democratic and Republican parties, powerful conservative interest groups and organized labor â¿¿ must hone their closing arguments for people who so far have been unmoved by months of impassioned appeals. "I don't think there's a huge persuadable universe out there in this campaign," Republican strategist Mark Graul said. With the undecided amounting to perhaps 2 to 4 percent, said Sachin Chheda, a Democratic strategist, "The challenge on both sides is to get people motivated to vote." Most Wisconsin voters already love or hate Walker. Tens of thousands of protesters swarmed the Capitol for three weeks last year after he made his push to end most public employees bargaining rights to help address the state's budget problems. Recall organizers were easily able to gather nearly a million signatures supporting his removal, but Walker's supporters also flooded his campaign with more than $25 million. The campaigns and special interests have spent about $40 million on a political blitz that has penetrated every household.