H. J. RES. 114
JOINT RESOLUTION
To authorize the use of United States Armed Forces against
Iraq.
Whereas in 1990 in response to Iraq’s war of aggression.

In summary:

Well, it seems that they were voting on reports that Iraq "continuing to possess and
develop a significant chemical and biological weapons capability,
actively seeking a nuclear weapons capability,
and supporting and harboring terrorist organizations;"

They voted to allow the pResident to enforce UN resolutions. 1441 required a Security Council vote prior to taking any military action.