Normally, that would be an opinion "concurring in the judgement" but not in all of the reasoning. Here 1. He disagrees with literally all of the reasoning. He

Normally, that would be an opinion "concurring in the judgement" but not in all of the reasoning. Here 1. He disagrees with literally all of the reasoning. He doesn't want to affirm the judgement because he thinks it's just plain wrong. 2. It's not clear he would agree with the outcome on this record either. He basically says the record isn't well enough developed on any of his points to figure out what should happen, and that the arguments he would make were forfeited. That suggests he may actually be in the camp of "i think all of the reasoning here is nonsense and wrong, and you forfeited all other arguments, so you lose". As a result he's dissented and literally written down "for the love of god, the next time someone appeals a case like this, please make the following arguments"