“Best believe somebody's paying the Pied Piper” goes a line from Eminem's Oscar-winning rap song “Lose Yourself.” According to New Zealand's high court, that somebody is the conservative National Party, and the Pied Piper is Eminem himself.

The Guardian reports that the rapper has won his copyright breach suit against the political party for using a version of his song in one of their campaign ads. Justice Helen Cull ordered the National Party to pay 600,000 New Zealand dollars ($415,000) plus interest to Eminem's publisher, Eight Mile Style. The amount was considered to be a “hypothetical license fee” that would have been paid to Eminem had the Party received permission to use the original.

The ad (seen below, along with the official video for Eminem's song) ran 186 times over an 11-day period during the 2014 election campaign. The National Party had bought the track, “Eminem Esque,” to use with the ad from a company called Beatbox. That company, in turn, had bought the license from music library Labrador, which is based in California.

Garry Williams, representing Eminem, told the court that “Lose Yourself” was an “iconic musical composition … a jewel in the crown of Eminem's catalogue.”

Lawyers for the National Party attempted to argue that “Lose Yourself” wasn't much of an original work during a two-week hearing in May that, according to The New Zealand Herald, often verged on the farcical as defense lawyers played different tracks to try and establish a difference between copying and imitation. One video of the proceedings, showing lawyers standing or sitting stock still as the Eminem track played in the courtroom went viral.

Justice Cull ultimately rejected the National Party's arguments in her 132-page decision. “The distinctive sound of 'Lose Yourself' is not limited by a 'melodic' line, but is a combination of the other instruments, particularly the guitar riff, the timbre, the strong hypnotic rhythm and the recurring violin instrumentation and the piano figure,” she wrote. “'Eminem Esque' sounds like a copy and is a copy of 'Lose Yourself.'”

Adam Simpson, a Sydney-based attorney who represented Eight Mile Style and “Lose Yourself” writers Jeff Bass and Luis Resto, said the ruling set “a major precedent” for copyright infringements. “This decision is a warning to soundalike music producers and their clients everywhere.”

National Party president Peter Goodfellow expressed disappointment with the ruling, but found it reassuring that the High Court recognized the due diligence the party took in seeking “extensive advice … from industry professionals” before purchasing the “Eminem Esque” track. “The judgment has also found that the party in using the track did not act flagrantly or in a manner which justifies the party being further punished,” he continued. The National Party has already lodged a claim against the suppliers and licensors of “Eminem Esque.”

As of press time, Cull has not ruled who will pay legal costs.