What was the Soviet foreign policy in the 20's? How did Soviet foreign policy affect their expansion? Any book recommendations or primary sources would be greatly appreciated!
Well, starting from 1920 and going right through to 1930, it changes an awful lot under successive governments.
1920 - 1923
The Russian Civil War is still being fought between the Red communists (led by Lenin) and the White anti-communists (including pro-tsarists, republicans, liberals, conservatives - generally anyone who didn't want to be communist). The Allied countries had intervened, the British sending in forces from the north, the Japanese with forces from the far east of the empire, the French and Americans with a polish route in to Russia and even a division of captured Czechs who had escaped imprisonment in central Russia and were now marching west. Obviously the Communist government in control of Moscow were not impressed and so there was a deep hatred of the West as well as a mistrust.
Anyway, by 1920 the Western forces were pulling back from Russia and allowing the White Russians to continue the war on their own. Of course the many different factions in the Whites quickly broke down and they were defeated, leaving the Reds victorious by 1922. The (soon to be) USSR never really forgave the Allied countries for invading and trying to stop their revolution. But with the country secure, they could focus on external affairs as well as domestic. Lenin's major thesis (what would later become known as Marxist-Leninism) was the spread of the Communist ideology throughout the world and incite a world proletariat revolution.
Germany: His main focus was Europe and especially Germany who he considered to be a prime candidate for worker led revolution due to its under-representation of the lower class and heavily industrialised economy. There was even a short lived Bavarian Soviet Republic between April and May of 1919. The German Revolution of 1918-1919 was very similar to that of Russia and was heavily influenced by it. First the ousting of the Kaiser then a Communist led revolution to install a Communist government. This was stopped by the Freikorp or "Free Corp" and German Army.
Hungary: The spread of Communism also affected Hungary. After a brief revolution in April of 1919, the Hungarian Soviet Republic was formed which tried to reclaim former Hungarian territory lost at the Treaty of Trianon leaving it with only 28% of its former land. After a few wars, the Soviet Republic of Hungary was brought down by the Romanian Army entering Budapest in August 1919.
Decline of Soviet Revolutionary Thought: The influence from the Communist Russian Empire on these revolutions was immense. They partly funded and armed revolutionary Communist groups in European countries. This antagonised the West to the degree that they felt they had to stop this destructive force. This aggression from the Wst was reciprocated by the Soviets. Foreign policy became more extreme and pushed more and more for a world-wide revolution. However, this did not mean an attempt by the Soviets to increase their territory, only to increase the spread of their ideology. The revolutionary phase officially ended in 1921 with the Red Army defeat in the invasion of Poland and in April of 1922, Germany and the USSR signed the Treaty of Rapallo where each renounced all territorial and financial claims against the other following the Treaty of Brest-Litovsk and World War I.
Post-Revolutionary Phase: These events effectively ended Leninist beliefs of starting a world-revolution. With the continued crushing of European revolutions and the normalisation of diplomatic relations between the Soviet Union and Germany, the Bolsheviks shifted their ideological focus to building Socialism inside the USSR rather than desperately trying to export it while still keeping the international Communist movement alive in the form of the Comintern. Soviet diplomats now focused on ending their country's isolationism.
1924
1924 was a real turning point in Soviet relations. In January the master mind behind the October Revolution and leader of the Soviet Union, Lenin, died. A power struggle quickly began. On an international stage too, things were changing.
Official Recognition: The United Kingdom, France, Italy, Sweden, Denmark, Austria, Norway and Greece formally recognized the Soviet Union as a country in 1924 giving it legal credence as a country. The Labour Party also came to power in the UK and started trading with the USSR; the first major country to do so. However, these friendly relations between the USSR and the UK would not last as in the run up to the 1924 General Election, the Zinoviev Letter was discovered by the Daily Mail describing the work between the Communist Party in the Soviet Union and the British Labour Party to create a proletariat revolution in the UK. Many historians now believe that this letter had little actual impact on the outcome of the Election but severely damaged the confidence of the Labour Party. In their place came the anti-Soviet Conservative Party, slowing Soviet rehabilitation in to Europe.
The Power Struggle: The two sides in this were also the two perspectives in foreign policy. One the one side you had Trotsky, the military genius who defended Leningrad and a whole lot else during the Civil War, advocating the world revolutionary position and on the other you had Stalin, the devoted Leninist, who also wanted world communism but saw it coming through a strong, independent Soviet Union who don't need no allies. Ignoring all the power struggle stuff since, you know, it's not foreign policy related; Stalin wins. With this the Soviet Union starts building up its industrial capacity, slowly at first but by the start of the 30s in leaps and bounds with the advent of the Five Year Plans.
NOTE: It has taken me nearly an hour to write this, I can continue if it's of help. International Relations is my strong point, especially those relating to the Soviet Union or the Cold War. Tell me if this is helpful and I'll continue. :)
Oh, also I would recommend both "Stalin: The Court of the Red Tsar" by Simon Sebag Montefiore and "A Brief History of 1917: Russia's Year of Revolution" by Roy Bainton. It doesn't cover international relations in a huge amount of detail until the Cold War but "The Penguin History of Modern Russia" by Robert Service is pretty good generally for an overview of the Soviet Union in this period.