On Nov. 8, 2017, Don filed a complaint against Phil's heirs — his third wife Patti and his two sons Jason and Chris — asking a judge to declare that he was the sole owner of the song, owing 100% of the song's copyright and royalties. As proof, Don presented the court a "release and assignment" declaration signed by Phil in that Phil was not the author of the song.
According to the evidence presented at trial, Don and Phil are both listed as “authors” on the original copyright registration for the Composition and in 1960 they assigned 100% of the worldwide copyright in "Cathy's Clown" to Acuff-Rose, which was later acquired by Sony/ATV Music (now Sony Music Publishing). They, however, still retained the contractual right to the so-called "songwriter's share" of royalties derived from the song.
Don testified during video deposition that he was 23 and Phil was 21 when they signed away those rights and never read the contracts. "We just kind of fell off the turnip truck," Don testified. "We were kids."
Over the years, Don and Phil expressed in interviews that they wrote the song together. During a 1972 interview, Phil said that Don had written most of the song but that he added some verses. However, Don now claims that he wrote the song alone and that the only reason he credited Phil with co-authorship of "Cathy's Clown" and several other songs was because he was told by Wesley Rose that it would make the Everly Brothers more popular if the public believed that they wrote their songs together, according to the court's opinion. Don told the court that the song was inspired by the break-up "for no reason" from his high school girlfriend, Catherine Castle Craven Coe, and the sound was inspired by the noise of "mules going down the path, down the canyon" from a Disney film Grand Canyon Suite.
Don testified that the brother's professional relationship soured by 1973 and he quit the duo. He said except for a call in 1980 that the brothers did not speak for ten years. "At their last show, Don was drunk and ‘messing up’ the lyrics, and the situation was so tense that Phil ended up smashing his guitar and walking off stage," according to the court's opinion. Don claimed that in 1980, he wrote Phil a letter saying "you can give me my songs back,” asking his estranged brother to correct the record legally that he was the sole writer on "Cathy's Clown."
There was evidence presented at trial that Don followed up the letter with a phone call to Phil in 1980. Don said he didn't remember this conversation, conceding to the court that during this period he would sometimes get "drunk and stoned." Joey Paige, the band's former bass player, testified he was at Phil's house that day when Don called and witnessed an angry phone call between the brothers. When Phil hung up, he told Paige that he told Don he was going to give back "Cathy's Clown" and later signed paperwork absolving himself of ownership to "keep the peace."
Don filed termination notices to regain his full copyrights to the song, and then after Phil's death his family also filed termination notices to regain the rights to the track.
Ultimately Judge Trauger decided that the evidence showed that Don "repudiated Phil's authorship of ‘Cathy's Clown' by letter and then by telephone call in 1980" and that Phil did not make any attempt within the three-year limitations period or within the remaining thirty-four years of his lifetime, to reclaim co-authorship status.