Evidence beyond the Documents:
This additional piece of evidence must be different from the evidence used to earn the point for contextualization.
A.
After the Civil War Abraham Lincoln was just the first of many US Presidents to encourage immigration through economic and politic measures (one of them was to give free land to anyone willing to work it). The country needed people to rebuild itself and to settle the west of the continent. And everyone was aware that there is plenty of space.
Due simply to the fact that it was their native land they were fighting on. Whereas the colonist they were fighting were new to the lands and not yet fully acclimated.
Texas was annexed in 1845, and Oregon was Spain's territory.
That is very true i assume