We did have a vote for a formal declaration of war against Iraq and here is part of the pertinent language from it:
Whereas the current Iraqi regime has demonstrated its continuing hostility toward, and willingness to attack, the United States, including by attempting in 1993 to assassinate former President Bush and by firing on many thousands of occasions on United States and Coalition Armed Forces engaged in enforcing the resolutions of the United Nations Security Council; . . .
(a) AUTHORIZATION- The President is authorized to use the Armed Forces of the United States as he determines to be necessary and appropriate in order to
(1) defend the national security of the United States against the continuing threat posed by Iraq; . . .
(c) WAR POWERS RESOLUTION REQUIREMENTS-
(1) SPECIFIC STATUTORY AUTHORIZATION- Consistent with section 8(a)(1) of the War Powers Resolution, the Congress declares that this section is intended to constitute specific statutory authorization within the meaning of section 5(b) of the War Powers Resolution.
(2) APPLICABILITY OF OTHER REQUIREMENTS- Nothing in this resolution supersedes any requirement of the War Powers Resolution.
Lending any legitimacy to the U.N. undermines our own national sovereignty.