The case involved a Colorado woman whose estranged husband kidnapped and killed their three children. She said Castle Rock, Colo., police were slow to respond to her frantic calls for help.
Jessica Gonzales had a restraining order against Simon Gonzales and argued that lack of immediate response violated the due process clause of the 14th Amendment.
Simon Gonzales died in a gunfight with police.
The bodies of his three daughters, ages 10, 9 and 7, were found in his truck.
In an 8-1 decision, Justice Antonin Scalia wrote courts in the past have rejected the idea that police cannot exercise discretion in deciding how to pursue their law enforcement duties. He also noted the Colorado law under which Jessica Gonzales obtained her restraining order says "shall" not "will" in describing how police should handle such situations.
"We conclude that Colorado has not created such an entitlement," Scalia wrote.