American troops leave Mexico when

Treaty of Guadalupe Hidalgo Ends the Mexican-American War

2, 1848, the Treaty of Guadalupe Hidalgo was signed, establishing the Rio Grande and not the Nueces River as the U.S.-Mexican border.

Explanation:

ummm? is that supposed to be a question or a but this is a reason he won re-election

explanation:

"despite progress in the war, lincoln and most political pundits were convinced that he would lose his bid for reelection in 1864. the country was war weary and the democratic party's nominee, george mcclellan, was likely to negotiate a peace treaty with the confederacy if elected." - loc.gov

a, c, & d are correct:

they wanted lands to settle the extra population.

they wanted new markets for english goods.

they wanted to avoid civil war.