Answer:
One key political issue that was raised due to the new U.S. territory gained as a result of the war with Mexico was the question of whether or not to allow slavery in these newly acquired territories. The war with Mexico had resulted in the United States gaining a large amount of land, including the present-day states of California, Arizona, New Mexico, Nevada, and parts of Colorado, Wyoming, Kansas, and Oklahoma. This new territory raised the question of whether or not to allow slavery in these areas, which was a highly contentious issue at the time and ultimately led to the American Civil War.