1. Uncle Sam. Uncle Sam looks to not want to be part of the League of Nation Bridge, and will not budge to place the USA stone into it.
2. The bridge represents the League of Nation, as suggested by the Billboard located on the West-side of the picture. The United States is missing from the bridge, as it continued to want to pursue the policy of isolationism, and wants nothing to do with foreign interests.
3. The sign is a ironic but true statement about the League of Nations. The League of Nations was designed by President Wilson following the end of World War I, but the U.S. Public forced the U.S. to stay out of the League itself.
4. The artist is suggesting that without the United States, the bridge of the League of Nations cannot be called a bridge (which is true). The U.S., being the founder and instigator of the League, failed to take part in it, allowing for the imminent collapse of the alliance. The UN following World War II, also instigated by the United States, is more successful, and lasts until today.
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