"A statutory limit has restricted total federal debt since 1917 when Congress passed the Second Liberty Bond Act. Congress has raised the debt limit seven times since 2001. Deficits each year since 2001 and the persistent increases in debt held by government accounts repeatedly raised the debt to or near the limit in place at the time. Congress raised the limit in June 2002, and by December 2002 the U.S. Department of the Treasury asked Congress for another increase, which was passed in May 2003. In June 2004, the Treasury asked for another debt limit increase. After Congress recessed in mid-October 2004 without acting, the Secretary of the Treasury told Congress that the actions he was taking to avoid exceeding the debt limit would suffice only through mid-November. Congress approved a debt limit increase in a post-election session, which the President signed on November 19, 2004."
CRS Report for Congress, RL31967
United States. Department of State, Foreign Press Centers, Bureau of Public Affairs: http://www.fpc.state.gov/