Because of the decision to host the first World Cup in Uruguay instead of in Europe, many European countries opted not to play.
Early World Cups were given to countries at meetings of FIFA's congress. The locations were controversial because South America and Europe were by far the two centers of strength in football and travel between them required three weeks by boat. The decision to hold the first World Cup in Uruguay, for example, led to only four European nations competing.
The next two World Cups were both held in Europe. The decision to hold the second of these in France was disputed, as the South American countries understood that the location would alternate between the two continents. Both Argentina and Uruguay thus boycotted the 1938 FIFA World Cup.