NEW YORK: Matisoff v. Dobi, 90 N.Y.2d 127, 659 N.Y.S.2d 209 (1997). A prenup must be "acknowleged"

A prenuptial agreement must be acknowledged in the manner of a deed in order to be enforceable. Matisoff v. Dobi stands for the principle that without a properly acknowledged agreement, a prenup is not worth the paper it is written on. By acknowledged the law requires that the notary public not only notarize the document, but acknowledge that you and your future spouse appeared and that you proved your identity by showing identification to the notary proving you are who you are. It comes down to boiler plate language and is really just a couple extra sentences accompanied by the notary’s signature. But without that statement of acknowledgment, the whole agreement is void on its face.