Wisconsin Supreme Court Justice David Prosser is running behind his challenger, Assistant Attorney General JoAnne Kloppenburg, in a state election that has gained national attention.

Prosser, the conservative-backed justice, trailed his liberal-backed challenger by 204 votes Wednesday afternoon with all of the state's 3,630 precincts reporting, according to The Associated Press.

Kloppenburg declared victory Wednesday afternoon, according to the Milwaukee Journal Sentinel

"I look forward to bringing new blood to the Supreme Court and focusing my energy on the important work Wisconsin residents elect Supreme Court justices to do," she said in a statement.

The race has drawn national attention because many consider it the first statewide referendum on GOP Gov. Scott Walker's controversial new union law, which curbs collective bargaining rights for unionized state employees.

The election's outcome could also have a tangible effect on the law — legal challenges to it are expected to reach the Supreme Court, but the Journal Sentinel noted that it is not clear if justices will take up the case before the winner is sworn in on Aug. 1. 

Political observers in Wisconsin say that the narrow margin will likely result in a recount. Should the result be upheld, it could tip the balance of the seven-member court from conservative to liberal.

It is rare for a challenger to unseat a state supreme court justice in Wisconsin. The winner receives a 10-year term.

-- This post was last updated at 4:00 p.m.