Answer :
I think the best way to summarize it is:
1) through a number of purchases:
Louisiana Purchase,
Gadsden Purchase
2)Through Anexation of the Republic of Texas (independent at the time)
3) and through war (The Mexican American-war, which lead to the Mexican Cession)
1) through a number of purchases:
Louisiana Purchase,
Gadsden Purchase
2)Through Anexation of the Republic of Texas (independent at the time)
3) and through war (The Mexican American-war, which lead to the Mexican Cession)
