The alliance between the foreign oil companies and the Colombian elite confronted its greatest challenge during the 1940s. Would state enterprises make the presence of foreign oil companies unnecessary in Latin America? When Mexico proved that nationalization and a state petroleum company were feasible alternatives, the Colombian elite had to rethink many assumptions. As a first step, the dispute over the expiration date of Exxon's Barrancabermeja concession required immediate attention. The Colombian elite could then ponder at leisure the alternatives that best suited their own interests. By 1946 the debate gave way to clashes, and a ferocious struggle ensued between competing factions within the elite and their respective allies as to what institution was best to harness the country's petroleum.