Stalin had already ordered scientists in the USSR to begin developing their own atomic bomb when they tested their first successful bomb on August 29, 1949.
Nikolai Novikov, the Soviet ambassador in Washington, sent a telegram in September 1946, informing Stalin that the USA wanted to use military power to dominate the world and were no longer willing to cooperate with the USSR.
The Soviet Union responded in a similar way, partly in retaliation for the telegram and mostly because Stalin wished to know the same information about the USA.
The bombs on Japan, particularly Hiroshima, accelerated the development of the atomic bomb in the Soviet Union and caused the USSR to build up their military to defend against the USA.
Kenneth R. Kenner's view of the Soviet Union was that peace between the two nations was not possible due to the Soviet Union's aggressive and suspicious nature.
The use of the atomic bomb made leaders like Lee, who were concerned about the internal problems of Britain, more confident in placing themselves under the protection of the USA.
The first telegram, sent in February1946, became known as the Long Telegram and was sent by George Kennan, who was working at the U.S. Embassy in Moscow.