What was the primary reason for U. S. involvement in Korea?

A. An imperialist hoping to annex (add) new colonies

B. The hope of expanding American frontiers westward

C. A fear of the international spread of communism

D. A humanitarian desire to help people improve their economies.

C. A fear of the international

Explanation:

"to reflect the policy of containment of communism, and keep the spread of communism steadily halted."

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