Senators McCaskill and Rockfeller introduced the Transparency in Assertion of Patents Act: S.2049 on February 26, 2014. The proposed legislation provides instruction for the FTC related to patent demand letter disclosures, unfair or deceptive patent assertions and civil penalties for unfair or deceptive patent demand letters.
A summary of S.2049, The Transparency in Assertion of Patents Act, is provided here for download (PDF).