What was the main outcome of the mexican war? a. after its defeat in the mexican war, the united states agreed to withdraw all american settlers from texas. b. the united states army occupied the entire country of mexico. soon, mexico would be annexed to the united states. c. mexico lost much of its northern territory, in what is today the western united states, to the united states. d. the united states won the war, but the alliance of great britain, france, and mexico would in time take back all of the territory that mexico lost.