They may not have lost themselves in the music or the moment, but a judge and nine lawyers in a New Zealand courtroom did listen politely to Eminem’s “Lose Yourself” as a copyright trial involving the country’s ruling political party began Monday.

The Detroit-based music publishers for Eminem are suing New Zealand’s conservative National Party, alleging the soundtrack for a 2014 election campaign ad copied the rapper’s acclaimed 2002 song. Titled “Eminem Esque,” the track has the familiar urgent, pulsing beat of the original.

The party has previously said it purchased the track through an Australian-based supplier and doesn’t believe it has infringed anyone’s copyright.

In 2014, when the case was filed, lawmaker Steven Joyce said he thought the use of the song was “pretty legal,” and that Eminem’s team “are just having a crack and a bit of an eye for the main chance because it’s an election campaign.” That response was widely ridiculed, including by comedian John Oliver on his show Last Week Tonight.

“Pretty legal? That’s not a concept that exists. That’s like being sort-of dead,” Oliver joked on the show.

Spokespeople for both Joyce and the National Party said Monday they wouldn’t be commenting while the case was before the court.

Garry Williams, the lawyer for Eminem’s music publishers Eight Mile Style, told the High Court in Wellington that the National Party had wanted a song that was edgy and modern but showed the party was dependable. He said the music fared better with focus groups than a classical piece.

He quoted from National Party emails, including one in which the song is described as an Eminem “sound-alike” and another in which an agent for the party wrote “I guess the question we’re asking, if everyone thinks it’s Eminem, and it’s listed as Eminem Esque, how can we be confident that Eminem doesn’t say we’re ripping him off?”

Williams said the emails showed it was “utterly clear” the party knew it was using a copyrighted song.

Speaking outside the court, Joel Martin, a spokesman for Eminem’s music publishers, said he was surprised the two sides hadn’t settled and that going to trial against an entity like a governing political party was unusual and extraordinary.

“The bottom line is we would never have permitted the use of the song in any political advertisement,” he said.

Martin said the publishers are seeking both a cash settlement for an undisclosed amount and an acknowledgement by the court that the National Party breached copyright. He said that by pursuing the case, they are showing they take copyright infringement around the world seriously.

He said the political views of the National Party were not a factor: “We are Americans and we don’t know about politics in New Zealand,” he said.

Judge Helen Cull ruled that some details in the case would remain confidential because they were commercially sensitive.

The judge-only case is expected to last about six days and will determine whether copyright was breached. The amount of any damages would be decided later.