While Polk awaited the Presidency, the trouble of Texas resurfaced.

Congress admitted Texas to the Union in a joint resolution passed the day before Polk's inauguration. Mexico was outraged. Inclusion in the United States would forever rule out the possibility of re-acquiring the lost province.

Furthermore, the boundary was in dispute. Mexico claimed that the southern boundary of Texas was the NUECES RIVER, the Texan boundary while under Mexican rule. Americans, as well as the incoming President, claimed that the boundary of Texas was the RIO GRANDE RIVER. The territory between the two rivers was the subject of angry bickering between the two nations. Soon it would serve as the catalyst for an all-out war.

Multiple Select Question
Using the source passage, what reasons caused the Unites States to go to war with Mexico?
A.
United States admitted Texas into the union.
B.
Protecting gold in California.
C.
Mexico could not get Texas back.
D.
Unites States wanted to annex all of Mecxico.
E.
Boundary dispute between Nueces and Rio Grande rivers.

A. United States admitted Texas into the union.

C. Mexico could not get Texas back.
E. Boundary dispute between Nueces and Rio Grande rivers.