Immigrants desired to come to the United States in order to obtain better job opportunities, and escape ongoing wars in their homeland. (Might not be the best, just kinda thought of it on the spot)
The common answer for this is that it is a joke. He was singing that because he was singing a few bars. This is a wordplay on the word bar of soap, and also on the fact that bars in music are <span>a segment of time corresponding to a specific number of </span><span>beats, so it's a pun actually.</span>
Wilson believed that fundamental flaws in international relations created an unhealthy climate that led inexorably to the World War. His 14 points outlined his vision for a safer world. Wilson called for an end to secret diplomacy, a reduction of armaments, and freedom of the seas. He claimed that reductions to trade barriers, fair adjustment of colonies, and respect for national self-determination would reduce economic and nationalist sentiments that lead to war.