News.com.com.com reports that the Federal Trade Commission has been using commercial blacklists to block inbound spam. Blacklists being blacklists, they're blocking some legitimate email too. The FTC being the FTC, some of this email consists of legitimate consumer complaints, including complaints about spammers.
Lee Tien of the EFF thinks the FTC's policy may not pass constitutional muster. In addition to the oft-cited guarantees about free speech and freedom of religion, the First Amendment also protects "the right of the people . . . to petition the government for a redress of grievances." The Petition Clause isn't exactly a thriving part of modern constitutional law: Congress routinely ignored it before the Civil War and the formal presentation of petitions to one's elected representatives has been largely superceded by campaign contributions. Still, it's not entirely a dead letter, and Tien's point gets at something fundamental about democracy: the government is supposed to listen to its citizens, not blacklist their email.
As a side note, one really has to wonder at the intelligence displayed by those enterprising souls who choose to send unsolicted bulk commercial email to the FTC.