The Cohen estate, it turned out, had refused the Trump campaign’s request to use the song, but the campaign had played it all the same.

“Had the RNC requested another song, ‘You Want it Darker’ … we might have considered approval,” noted a lawyer for the Cohen estate in a wry statement.

This sort of controversy is hardly new, however. Every selection season brings a new spate of headlines about a copyright kerfuffle involving candidates’ unauthorized use of songs. In the case of Trump, his campaign has attracted a torrent of criticism from the likes of the Rolling Stones and the estate of Tom Petty over its use of “I Won’t Back Down” and “You Can’t Always Get What You Want.” The campaign of his 2016 opponent, Hillary Clinton, also got into trouble for using Bikini Kill’s “Rebel Girl” without permission.

Meanwhile, rocker Neil Young recently took the unusual step of filing a lawsuit against the Trump campaign for playing “Rocking in the Free World” without his permission.

All of this raises the question of why politicians continue to flagrantly use songs without permission, especially in the U.S. where both major parties regularly call for aggressive protection of intellectual property.

The simple answer is because they can. U.S. copyright law provides for a so-called blanket licensing regime when it comes to public performances—meaning that those wishing to play a song can go to one of two royalty collection agencies, ASCAP and BMI, and pay a fee to use their catalogue of songs.

What’s more, the Justice Department has imposed a decree on both agencies for decades that requires them to license songs to all comers. The order is the result of the agencies cartel-like behavior in the past, and ensures they can’t arbitrarily withhold access to songs or gouge those who license the music.

The upshot is that blanket licensing has made it easy for everyone from cover bands to juke box operators to restaurants to play music in public. But as the Hallelujah episode shows, it also means groups can use hit songs for propaganda purposes, even if the songwriter believes such use is wrong or disrespectful.

In recent years, artists have begun asserting clauses that exclude the use of songs at political rallies from the blanket licensing regimes. And other musicians have claimed such use diminishes the value of their songs, and infringes on their so-called right to publicity.

But these legal arguments are very much untested, and it’s unclear if the Justice Department rules allow BMI and ASCAP to create an exception in the case of political rallies—skeptics say a venue that obtains a license is covered, regardless of the purpose of a given event. As such, Neil Young’s copyright lawsuit is likely to provide an important test case for whether musicians are able to stop politicians using their songs.

Ironically, despite its penchant for aggressive copyright enforcement, the U.S. lacks a system called “moral rights” that is common in many other countries, and would help the likes of Young and the Cohen estate, according to McGill law professor Richard Gold.

Gold, an authority on intellectual property, explains that moral rights permit artists to block the use of their work for a cause in which they don’t believe. In their absence, it can be hard for musicians to stop the use of their songs—even if it could lead to a false sense of endorsement.

“That is what happened here: by the Trump campaign using Cohen’s iconic song, some may be led to the (wrong) belief that Cohen supported Trump’s cause, even in death,” says Gold.