It is a bit funny to see these films with a political message today, when that message is not allegorical or hinted at, but spoken right into your face. On the other hand, communication was different in the 1950s, and so was political logic and diplomacy. The whole film only works because the alien with the vastly superior technology, ability to fly from wherever in just five months, produce impregnable metal and indestructible robots – this alien is not able to just send out a radio broadcast or tv message all over the world’s channels, making sure that his message about love peace and happiness and the end of all violence is heard by all the world’s leaders at the same time? Why bother to bring them together? Because that gives you more time to contact the superbrain scientist who believes you and brings his fellow top scientists from all over the world to come and witness your statement. It is just such a good guy, that alien man that looks just like people on Earth do: when he makes the world stand still for half an hour by cutting off electricity, he makes sure nobody is harmed by leaving out the hospitals, airplanes in flight and other vital instruments. He is not beyond threat, actually he came to Earth in order to explain his threat.
So in summary: nice alien, good cause, friendly warning… why did we not listen, I wonder?
http://www.rottentomatoes.com/m/1005371-day_the_earth_stood_still/