[steveegg]

Roberts would have to agree in full with at least one of 90% of the time. I guess the full agreement part may make it difficult to track, but I am confident Roberts will be in full agreement with at least one of them 90% of the time.

Which does not answer my question on whether a separate concurrance on a case where they also joined in an opinion (not in part) would count as a "full" agreement. The reason I ask is that Thomas not only fully-joined in the dissent that O'Connor wrote in Kelo, but he also wrote a separate dissent.

[Always Right]

Which does not answer my question on whether a separate concurrance on a case where they also joined in an opinion (not in part) would count as a "full" agreement. The reason I ask is that Thomas not only fully-joined in the dissent that O'Connor wrote in Kelo, but he also wrote a separate dissent.

That is kind of tricky, but if they both sign the same dissent, it sounds like full agreement. That would just be a matter of Thomas wanting to get a few more cents in.

[AntiGuv]

So far as I know, Justice Thomas would then be considered in full agreement with Justice O'Connor for statistical purposes. This is the summary of the Kelo decision:

STEVENS, J., delivered the opinion of the Court, in which KENNEDY, SOUTER, GINSBURG, and BREYER, JJ., joined. KENNEDY, J., filed a concurring opinion. O’CONNOR, J., filed a dissenting opinion, in which REHNQUIST, C. J., and SCALIA and THOMAS, JJ., joined. THOMAS, J., filed a dissenting opinion.

So, Justice Thomas joined Justice O'Connor's dissent in full, but then filed his own dissent as well. Joining an opinion in full doesn't mean you don't also have an additional opinion about the matter.