On Thursday the Supreme Court unanimously ruled that Carol Bond, a Pennsylvania microbiologist who took revenge on an ex-friend who had been impregnated by Bond's husband, can challenge her federal conviction on 10th Amendment grounds. After learning of her husband's affair, Bond spread caustic substances on her friend's mailbox, car door handle, and front doorknob, as a result of which the woman suffered a minor burn. But instead of being tried in state court on assault charges, Bond was convicted under a federal statute that makes it a felony to knowingly possess, for nonpeaceful purposes, a chemical that "can cause death, temporary incapacitation or permanent harm to humans." Bond argued that the statute, which implemented the Chemical Weapons Convention of 1993, overstepped the federal government's authority, impinging on criminal matters that are traditionally the province of the states. In 2009 the U.S. Court of Appeals for the 3rd Circuit rejected her challenge, ruling that a defendant may not use the 10th Amendment to appeal a conviction. The Supreme Court overturned that decision and sent the case back to the 3rd Circuit, instructing it to address the 10th Amendment issue.
Writing for the Court, Justice Anthony Kennedy rejected the 3rd Circuit's conclusion that "to argue that the National Government has interfered with state sovereignty in violation of the Tenth Amendment is to assert the legal rights and interests of States and States alone." To the contrary, he said, "Bond seeks to vindicate her own constitutional interests," claiming "injury from governmental action taken in excess of the authority that federalism defines." Kennedy also emphasized the importance of the federalist principles at stake:
The federal system rests on what might at first seem a counterintuitive insight, that "freedom is enhanced by the creation of two governments, not one."…The Framers concluded that allocation of powers between the National Government and the States enhances freedom, first by protecting the integrity of the governments themselves, and second by protecting the people, from whom all governmental powers are derived.
Federalism has more than one dynamic. It is true that the federal structure serves to grant and delimit the prerogatives and responsibilities of the States and the National Government vis-à-vis one another. The allocation of powers in our federal system preserves the integrity, dignity, and residual sovereignty of the States. The federal balance is, in part, an end in itself, to ensure that States function as political entities in their own right.
But that is not its exclusive sphere of operation. Federalism is more than an exercise in setting the boundary between different institutions of government for their own integrity. "State sovereignty is not just an end in itself: 'Rather, federalism secures to citizens the liberties that derive from the diffusion of sovereign power.' "
Previous coverage of the case here and here. SCOTUSblog's rundown here. The last time the Supreme Court dealt with the 10th Amendment, it approved post-sentence commitment of "sexually dangerous" prisoners as a legitimate federal function. That case involved people who had already been convicted under federal laws whose constitutionality was not at issue, while this case presents the question of whether fighting terrorism and the proliferation of chemical weapons gives Congress license to make a federal case out of a domestic spat.
Addendum: The Goldwater Institute's Darcy Olsen calls Bond. v. U.S. "one of the best and most important decisions ever on federalism," since it establishes that "individuals have standing to challenge federal laws as violations of state sovereignty under the 10th Amendment."