What was the result of US territorial gains after the Mexican American war? *

Explanation:

Under the Treaty of Guadalupe Hidalgo, which settled the Mexican-American War, the United States gained more than 500,000 square miles (1,300,000 square km) of land, expanding U.S. territory by about one-third. ... Read more about the Treaty of Guadalupe Hidalgo.

Combatants: United States, Mexico

Location: United States

monarchy doesn’t have to have the hereditary element. there have been elective monarchies in the past where you choose your king-for-life and when he dies elect someone else for the job.