Answer:
It wasn't governed very fairly, hence the Boston tea party
Explanation:
<span>Prior to the Mexican American war president Polk sent John Slidell to Mexico to negotiate an agreement between that the Rio Grande River would be the southern border of Texas. ... The United States annexed the territory of California in 1848 following its victory in the Mexican-American War.</span>
That is was the key stone to their life and they needed to protect it at with everything they had to offer,
