...If enacted, the new law will almost certainly be challenged in court. The Constitution does not grant the federal government any general police power -- prosecuting crime is primarily a state and local responsibility -- and it is far from clear that the Supreme Court would go along with a congressional attempt to federalize such a broad swath of criminal law.

Which is just as well, since the new law will not serve any legitimate criminal-justice end. Every crime that would be covered by the bill is already a felony under state law. Each one can already be prosecuted and punished. Its name notwithstanding, the Matthew Shepard Hate Crimes Prevention Act will not prevent any hate crimes. Nor is there anything it could have added to the prosecution of Shepard's killers, both of whom were convicted of murder and sentenced to two consecutive life sentences.

Supporters of hate-crime legislation often invoke the victims of such high-profile murders. After James Byrd Jr., a black man, was savagely dragged to his death in Jasper, Tex., by three white men, Senator Ted Kennedy introduced a federal hate-crime bill and brought Byrd's daughter to Washington to testify in its behalf. But Texas authorities needed no help from Washington to bring Byrd's murderers to justice. Two were executed and the third is behind bars for life. Last month, the National Center for Lesbian Rights declared that the murder of Angie Zapata -- a transgender person bludgeoned to death in Colorado last summer -- showed why an expanded federal hate-crime statute was "long overdue." Yet even without such a statute, Zapata's killer was readily convicted in state court of first-degree murder and sentenced to life without parole...