Castle Rock v. Gonzales, Supreme Court of the United States, June 27, 2005 [ruling 7-2 that a woman whose estranged husband murdered her three children did not have a constitutional right to police enforcement of the restraining order in place against her husband]. Excerpt from the opinion, by Justice Scalia:

We conclude, therefore, that respondent did not, for purposes of the Due Process Clause, have a property interest in police enforcement of the restraining order against her husband. It is accordingly unnecessary to address the Court of Appeals' determination (366 F. 3d, at 1110—1117) that the town's custom or policy prevented the police from giving her due process when they deprived her of that alleged interest.

Read the full text of the opinion here [PDF]. Reported in JURIST's Paper Chase here.