In May 1940, Päts believed that the best option for Estonia would be to follow Soviet guidelines until the German-Soviet war. In case of such war, "Estonia would be saved". However, on 16 June 1940, the Soviet Union delivered an ultimatum to the Estonian government. Päts's first reaction was to consult with the businessman Joakim Puhk. The Estonian government was forced to accept the ultimatum and a full Soviet invasion followed on 17 June 1940.