MADISON, Wis. -

Both sides of the recall election targeting Wisconsin Gov. Scott Walker are prepared for a razor-thin margin as the Republican tries to become the first U.S. governor to successfully fend off a recall effort.

A brief but bruising campaign ends with Tuesday's election pitting Walker against Democratic Milwaukee Mayor Tom Barrett. It's a rematch of the 2010 governor's race in which Walker defeated Barrett by 5 percentage points.

The effort has shattered state campaign spending records and further divided an already polarized state.

Walker said he's focused on turning out voters who have supported him in taking on public-employee unions. Barrett is seeking to capitalize on the anger over Walker's conservative agenda that began building almost as soon as he took office in January 2011.