This summer the Supreme Court is going to hear the arguments of Jimmy Page and the band Spirit in whether Led Zeppelin’s iconic song “Stairway To Heaven” plagiarized Spirit’s 1968 song “Taurus.” Now, anyone who read my Greta Van Fleet review knows that I am not one to defend Led Zeppelin, but this is probably the one time in their history that they’ve been innocent, and whether the court finds that or not has great significance to copyright law as it applies to music broadly.

Music plagiarism lawsuits started to spring up en masse after 2015’s suit against Robin Thicke and Pharrell Williams by the Marvin Gaye family over the song “Blurred Lines” and it’s similarities to Gaye’s “Got To Give It Up.” This case broke some of the established rules of music copyright. In music, the two things you need to file to copyright a song are the words and the chords (as Robbie Robertson will eagerly tell you, arrangement has no bearing on songwriting, legally). But this case was reliant mostly on the use of a descending bass line and similar production styles. This high profile revisiting of what music copyright is led to a massive increase of lawsuits in the last four years, with forensic musicologists being in high demand ever since.

Now, this isn’t to say that suing over plagiarism in music began in 2015. The first high profile music plagiarism case was probably when Chuck Berry sued the Beach Boys for similarities between “Surfin’ USA” and “Sweet Little Sixteen,” and the most infamous of the 21st century was when George Harrison was found guilty of “unintentional plagiarism” by a judge over similarities between “My Sweet Lord” and a song by The Chiffons. Of course, the highest profile offenders were Led Zeppelin, who settled out of court with such legends as Howlin’ Wolf, Memphis Minnie, Willie Dixon, and Sonny Boy Williamson, although accusations of additional plagiarism by artists like Bert Jansch and Jake Holmes that haven’t gone to court have been circling since 1969 when they lifted “Dazed And Confused” from Holmes word for word.

Which brings us back to “Stairway.” The thing that makes this suit stand out in the history of Zeppelin plagiarism is that Jimmy Page actually let it go to court. Never before has Zeppelin stood before a judge to assert their innocence, which is why I decided to give it a closer look than just “oh, Zep stole from another artist.”

The trouble with “Taurus” isn’t that it’s not a very similar composition to “Stairway”’s intro, but rather that the song is so rudimentary, it’s hard to make the case that Jimmy Page couldn’t have possibly come up with the intro to “Stairway To Heaven” without hearing it. If you want to go in depth into the song, YouTuber 12Tone did an excellent dissection of it, although only the first two and a half minutes pertain to the case. The iconic intro is little more than a series of arpeggios of chords descending a half step down (one fret of the guitar, for those not familiar with music terminology) each time. Shoot, I’m pretty sure I wrote a song like that when I was 17, hadn’t heard Spirit or Zeppelin, and had only been playing for about 6 months.

But a lot is riding on this case. A suit about whether Ed Sheeran plagiarized another Marvin Gaye song (this time filed by a co-writer’s estate, not the Gaye estate), has been postponed to hear what SCOTUS has to say about Led Zeppelin–and if you want to know why that suit is bogus, Adam Neely has a great video on that. If the Supreme Court rules with Spirit, artists’ ability to reuse cliches–which has been the backbone of popular music since the Bristol Sessions–will be in danger, and the entire musical landscape might never be the same again.

Elizabeth von Teig is a musician and author living in Brighton, Massachusetts. Her expertise is classic rock, folk punk, and the blues.