Section 1125(c)(1) of Title 15 (link here) provides as follows: “Subject to the principles of equity, the owner of a famous mark that is distinctive, inherently or through acquired distinctiveness, shall be entitled to an injunction against another person who, at any time after the owner’s mark has become famous, commences use of a mark or trade name in commerce that is likely to cause dilution by blurring or dilution by tarnishment of the famous mark, regardless of the presence or absence of actual or likely confusion, of competition, or of actual economic injury.”
Current law however also provided that a ownership of a valid registered mark was a complete bar to an action under state law, seeking a similar dilution remedy. 15 USC 1125(c)(6). The law, however, was inartfully worded such that it could be and was read to bar even claims based on federal law.
This “error” in the statute was corrected in 112 HR 6215 (http://docs.house.gov/billsthisweek/20120910/BILLS-112hr6215-SUS.pdf ) by making it clear that ownership of a federal registration is not a bar to an action for dilution under federal law. Though this is a “technical” change, the old law applies prior to the date this law came into effect, and at least one tribunal has read the old law literally, barring a claim for dilution against a federal trademark holder.