Here's one from the Federal Circuit that doesn't break new ground, but is founded on an arcane point of Florida law.
Rogers v. United States, No. 13-5098 (Dec. 28, 2015) is a rails-to-trails case, so the background is pretty standard: old railroad right-of-way, abandoned, followed by a NITU (Notice of Interim Trail Use), which ripened takings claims for the reversionary interest. Followed by standard government tactic: avoid the takings by showing that the reversionary interest isn't property.
And that's where Florida law comes in, the question being whether the deeds which originally conveyed the land to the railroads conveyed a fee simple interest or something like an easement. The Court of Federal Claims concluded the deeds conveyed a fee simple interest (the deeds used the words "fee simple," after all), but on appeal, the Federal Circuit was not as sure because there was no "controlling" state law authority. So it asked the Florida Supreme Court, via the certified question process: do the words "fee simple" in a conveyance of property to a railroad really mean fee simple, or something else?
When the Florida court responded and concluded that the words "fee simple" really do mean fee simple ("no policy of the State of Florida limits the railroad’s interest in the property regardless of the language of the deed"), the Federal Circuit had no choice at that point but to hold that the takings claims failed:
Appellants were the ones to suggest that we certify the question to the Florida Supreme Court if there is any doubt as to Florida law. Appellants Reply Br. 26-28. The Florida Supreme Court has now answered, and we find its opinion to have removed all doubt as to the correct result in this case. Its opinion confirms that, under Florida state law, a railroad can acquire either an easement or fee simple title to a railroad right-of-way and that no statute, state policy, or factual considerations prevails over the language of the deeds when the language is clear.
Slip op. at 16.
Rogers v. United States, No. 13-5098 (Fed. Cir. Dec. 28, 2015)