What was a primary motivation for American pioneers to travel to the Southwest?

Which of these belongs to the united states after the spanish american war ?

Why didn’t the united states participate in the league of nations? the u.s. senate did not want the country to join. president wilson did not want the country to join. the league of nations was only for european countries. the league of nations had failed to prevent world war 1

Why is the end of the cold war tied to the american domestic economy during this time?