As he explains:
It's awful on many fronts. It would allow a court to effectively shut down a site operated out of Brazil, or France, without any adversary hearing (unless, I suppose, "the domain name" itself comes into court to argue the case) or any reasoned determination that the site actually is engaged in unlawful activity. There is a name for that in our law: "prior restraint," and we don't like them even in cases where truly compelling governmental interests are at stake, let alone where the purpose is merely to protect the rights of copyright and trademark owners.
Check out the full details here:
[Update] Popular Instapundit blogger Glenn Reynolds writes: "If I have to choose between getting rid of copyright and getting rid of free speech, I'll say goodbye to copyright. The folks at Big Content, and their shills like Leahy, seem to want to make me choose."