Even supporters acknowledged the difficulty ahead in passing an updated version of a similar ban that became law in 1994 and expired without congressional re-authorization a decade letter.

CNN: Senate panel passes ban on assault-style weapons

He did not have a congressional authorization but he did provide a letter, consistent with the War Powers Act.

WHITEHOUSE: Press Briefing

Your letter of invitation requested that I comment on the workforce provisions in the recently enacted National Defense Authorization Act (NDAA) for FY 2008 and the Accountability in Government Contracting Act of 2007 (S. 680), which passed the Senate on November 7, 2007.

WHITEHOUSE: Testimony of Paul A. Denett