Republican Gov. Scott Walker's recall victory in Wisconsin sets up what's now expected to be a hard-fought presidential battle for the Midwestern state.

Walker's solid victory serves as a warning for President Barack Obama about the potential hurdles he faces as he fights to hang onto a Democratic state he won comfortably in 2008.

The victory gives Republican challenger Mitt Romney a reason to
feel optimistic about his chances of winning a state that has voted
for the Democratic nominee in the past six elections.

The Wisconsin election tested voter attitudes toward Walker's
aggressive governing style as well as a law that ended collective
bargaining for most public employees and teachers.

In the coming days, national Republicans and Democrats alike
will re-evaluate the Wisconsin political landscape.