The Wisconsin Supreme Court election that became a referendum on Gov. Scott Walker’s (R) crackdown on public employee unions remains too close to call.

With 99 percent of precincts reporting, conservative Justice David Prosser led his more liberal challenger, state Department of Justice prosecutor Joanne Kloppenburg, by 585 votes out of nearly 1.5 million cast on Tuesday.

The Associated Press said it would take several hours, or most of Wednesday, to determine a final vote tally. But the Milwaukee Journal Sentinel reported the increasing likelihood that the contest will come down to a recount, a process that could delay a resolution in the closely watched race for weeks or even months.

The Supreme Court contest, conducted as part of the usually sleepy Badger State’s spring elections, attracted national attention and millions of dollars from outside groups.

Tuesday’s affair was technically an election to fill one of the seven spots on the state’s high court for the next 10 years. Prosser, a former Republican Speaker in the state Assembly, has served in the state Supreme Court since 1998. But the tea party movement and liberal groups transformed the contest into a national referendum that may signal a larger shift in national politics.

The Tea Party Express, the conservative machine behind unlikely grass-roots Republican primary victories in Delaware and Alaska last fall, dubbed Tuesday “the most important election of the year.” Organized labor poured volunteers and money into the race, which they suggested signaled an awakening of sorts among the labor movement that wasn’t particularly motivated or unified in the 2010 midterm elections.

The Tea Party Express sounded confident in a Wednesday morning email to supporters: “We … will remain vigilant, determined not to allow another Al Franken type recount fiasco to deprive the voters of Wisconsin the righteous winner in this race.”

The contest could shift the balance of power in the state’s high court, where conservatives hold a 4-to-3 majority. A Kloppenburg victory would give the left a narrow majority and could play a prominent role in any effort to overturn Walker’s restrictions on collective bargaining.

The nationalization of Wisconsin politics isn’t expected to end anytime soon, however.

Republicans and Democrats are pushing to recall state Senators involved in the collective bargaining fight. Republicans, having made significant gains during the 2010 midterms, have the most to lose.

Last week, local Democratic activists submitted the first batch of signatures needed to recall their eight targets. Assuming the state certifies the signatures, a special election to recall GOP state Sen. Dan Kapanke could be scheduled in mid-summer. And Democrats are on the way to forcing new elections in seven more districts held by Republican state Senators.