Your answer is.....The flag
"As a result of some former Confederate states' refusal to ratify the Fourteenth Amendment,"
Possible answer = Congress established military rule in the South.
No, the Monroe Doctrine does not provide U.S. sympathy for the new revolutionary governments in South America. You're thinking of the "Good Neighbor" policy.
The trails and the conditions were very rough, and they struggled to traverse across these trails. Also, the weather was very bad and many of the settlers got sick and died from disease along the way