Stockphotographer.info has a post up about the Trademark Dilution Revision Act, which was passed by the House last year and has now gone to by the Judiciary Committee. The post says that "exceptions for fair use, ... commentary, etc. ... could disappear and would be no defense to claims of infringement," but I think that may be something of an overstatement. The bill provides that a fair use defense would still be available upon a showing that the challenged use is not as a designation of product source but is, instead, a descriptive use, or one intended as parody, commentary, or criticism.
UPDATE: This piece in Ars Technica agrees with my take: "Clearly, then, the wild claims made above about eliminating 'fair use... reportage, commentary, etc.' don't hold up when you examine the bill. Fair use of trademarks in several different forms is explicitly allowed, as is all news reporting and commentary that feature such marks."