What two factors led to the US being considered a powerful nation during World War I? The battle of Belleau Wood proved to the world the strength of the US armed forces. The economic strength of the US led to greater respect from leaders of other countries. The advancement of US military weapons was greater than any other country. The Battle of Amiens was a turning point in the Allies' favor following US entry. The Treaty of Versailles turned the US into a peacekeeping nation.