Why was the United States at the forefront in negotiating many of the international treaties of the 1920s? The U.S. was regarded as a fair and neutral nation. Americans really believed that they could outlaw war. The U.S., as the world's richest nation, was vital to any international agreements. Presidents Harding and Coolidge had a plan to bring the United States into the League of Nations.
"The U.S., as the world's richest nation, was vital to any international agreements" would be the best option from the list since this was two years after the US had left World War II, after they have become prominent players on the world stage.
