The case of Riggs v Palmer
examined whether a grandson who had killed his grandfather should be allowed to inherit the grandfather's estate. In October of 1889, the Court of Appeals
of New York
The Laws of New York relating to the probate of wills and the distribution of estates will not be construed so as to secure the benefit of a will to a legatee who has killed the testator in order to prevent the revocation of the will. (Riggs v Palmer 22 N.E. 188 (1889))
This case is an interesting study because it is a case where a majority of the judges ruled contrary to the existing statutory law in favour of the principles of common law. Specifically, while the laws dealing with inheritance (as they were at the time) specifically stated that "No will in writing, except in the cases hereinafter mentioned, nor any part thereof, shall be revoked or altered otherwise," the majority judges nevertheless invalided the will, on the premise that the authors of the law intended that the Court should exercise this kind of discretion when necessary. This is an example of a Court choosing the principles of natural law over the principles of legal positivism. Also significant is the reverse argument made by the minority judges, to the effect that the written law must be the sole deciding factor in this case.
A transcript of the case, as well as questions for consideration, may be found at http://www.law.berkeley.edu/faculty/rubinfeldd/LS145/riggs.html