A racial-profiling lawsuit over the New York Police Department's "stop, question and frisk" policies is now in the hands of a judge whose decision is expected within weeks. Many New Yorkers watched the two-and-a-half-month trial nervously, concerned that a ruling against the NYPD by U.S. District Court Judge Shira Scheindlin could spell an end to a police practice that helped the city achieve an astonishing drop in violent crime.

But non-New Yorkers would do well to worry about the case too. A decision against the...