I think the case can be judged by ANY individual with a musical ear.
Just listen to “Blurred Lines” and Marvin Gaye’s “Got to Give It Up”.
https://www.youtube.com/watch?v=ziz9HW2ZmmY
Regardless of the jury’s racial makeup, the similarities are very obvious.
I listened to it yesterday trying to see for myself if I thought they were the same. The beat sounds similar between the two, but I can't say this is enough to convince me that the one is a rip-off of the other.
I will also admit that I have never heard either song until yesterday.
Before I agreed that the one song was a substantial rip-off of the other, I would like to see the arrangements of both and perhaps play them a bit myself.
As it stands, I haven't yet been able to identify any specific melody that is common to both songs. A style of beat yes, but I don't particularly regard beats as the most significant aspect of a song. Melody's are the essential aspect, and I can't tell that the Melody has been copied from the Marvin Gaye song to the Robin Thicke song.
Of course I haven't spent a lot of time on this, and perhaps with more comparison I might see what other people are claiming in regards to similarity.