The special recall election for Wisconsin's governor has set the stage for the first major showdown between the two men in charge of the Republican and Democratic governors' associations, Virginia Gov. Bob McDonnell and Maryland Gov. Martin O'Malley.

Eighteen months of political turmoil in Wisconsin comes down to a rematch of the 2010 election between Republican Gov. Scott Walker, who ignited the recall after stripping collective bargaining rights from public employee unions, and Milwaukee Mayor Tom Barrett, the victor in Tuesday's Democratic primary.

For McDonnell and O'Malley, the special election is a key test in a pivotal electoral state before the two face off in this year's main contest: 11 gubernatorial elections in November.

Both McDonnell's Republican Governors Association and O'Malley's Democratic Governors Association are already heavily involved in Wisconsin.

McDonnell's RGA began airing ads March 23 and launched a new 30-second spot Wednesday slamming Barrett. O'Malley's DGA joined with a liberal Wisconsin group to run anti-Walker ads for more than a week and will continue to work with other state groups on advertising and get-out-the-vote drives.

The third recall of a governor in U.S. history is scheduled for June 5.

"While Wisconsin remains a Democratic-leaning state heading into the November election, Wisconsin voters have already rejected Walker's overreaching ideological agenda at the expense of job creation," said O'Malley. He called Walker's anti-union policies "bad for the GOP brand."

A Walker victory, McDonnell said, "would show that political leaders are able to take on the toughest challenges and govern with the next generation in mind."

Walker has become a hero in conservative circles for curtailing union power in Wisconsin and inspiring similar efforts in Republican-controlled statehouses in Ohio and Michigan. His cuts-first approach to the state's budget won praise from Republican leaders nationwide, including McDonnell.

Democrats counter that Walker's tactics polarized the state and led to tepid job growth, undermining his own promise to create 250,000 jobs in his first term.

"This race has raised issues that became important in other states following 2010 Republican victories," said Charles Franklin, director of Marquette Law School Poll. "While the styles have differed across those governors, many of the issues, especially how to deal with budget deficit, how to deal with long-term pension benefits and shorter-term employee costs -- in that extent, Wisconsin is a bit of harbinger."