In 1990, iraq invaded kuwait . as a result, the united states military along with a few allied forces the iraqi army out of kuwait. why did the us get involved in this dispute?

The United States got involved kuwait for an array of factors.  The United States  initiated an extensive public relations campaign to justify the reasons for war.  Prior to Iraq's invasion of Kuwait, the had been a Cold War ally which further complicated things for the United States.  So really It was to provide humanitarian aid to kuwait and to prevent further war.