In 1938, the British severed diplomatic relations with Cárdenas' government, and boycotted Mexican oil and other goods. An international court ruled that Mexico had the authority for nationalization. With the outbreak of World War II, oil became a highly sought-after commodity. The company that Cárdenas founded, Petróleos Mexicanos (or Pemex), later served as a model for other nations seeking greater control over their own oil and natural gas resources. In the early 21st century, its revenues continued to be the most important source of income for the country, despite weakening finances. Cárdenas founded the National Polytechnic Institute in order to ensure the education and training of people to run the oil industry.