Barbara Lee explains the rationale behind her "lone vote" in her own words on her own website: REP. BARBARA LEE’S (D-CA) VOTES ON LEGISLATION REGARDING THE TERRORIST ATTACKS OF SEPTEMBER 11, 2001 :

"On Friday, September 14, I voted against H. J. Res. 64, which ceded Congress’s future authority to the President regarding the use of military force in response to the terrorist attacks. Our Constitution provides for checks and balances between our branches of government. This resolution does not obligate the President to report back to Congress after 60 days, as was required by Congress during the Gulf War, about the actions our military will take. Additionally, this resolution authorizes an open-ended action and significantly reduces Congress’s authority in this matter. We must bring the perpetrators of this horrific action to justice. But during this period of grief, mourning, and anger, the U.S. Congress has a responsibility to urge the use of restraint so that the violence does not spiral out of control and to consider all of the implications of our actions."