What is one difference between open and closed primary elections?

What principle did president truman invoke in sending u.s. troops into south korea without first asking congress to declare war?

What are the contributions of the byzantine empire

Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in liberty, and dedicated to the proposition that all men are created equal. —"the gettysburg address," abraham lincoln which quotation correctly uses an ellipsis to shorten lincoln’s words?