The Soviet Union was underpowered. Although Stalin insisted at the Potsdam Conference that Britain and the United States agree to let the Soviet Union take over the Black Sea Strait in place of Turkey, Britain and the United States did not object in principle. But then Turkey shouldered the Soviet Union and threw itself into nato's arms at the right time. Stalin therefore did not dare to fight the idea of the Outlet of the Black Sea again. Russia's history of its eyeing the Black Sea Strait dates back to the time of Alexei I, peter the great's father.
At the outbreak of World War II, Turkey had the bitter lesson of the wrong side of the First World War, and this time it could be learned, and this time Turkey bet on both sides at the same time, providing resources for Germany on the one hand, and ports for British troops on the other. In this way, neither side wants to move the country. When the war between the Soviet Union and Germany broke out, Turkey thought that once the Soviet Union was defeated, Turkey could seize the opportunity to occupy the Caucasus region, and the Soviet Union naturally knew this, so some troops never dared to move, and these troops were on the alert of Turkey.
For the Soviet Union, taking the opportunity to annex some of the smaller surrounding countries was the right way, including, of course, to obtain the coveted access to the sea. The Soviet Union's means to this end was to annex it by force, and if it did not, it would support the puppet regime. However, when facing Turkey, the Soviet Union hesitated, because the Outlet to the Black Sea was so important that not only the Soviet Union saw this, but britain and the United States also saw this. The Soviet Union initially acted on the principle of negotiation, saying that the Soviet Union only needed to trust the strait, and the United States also approved it. But it was not yet the end of the war against Germany.
Stalin had to be resolute, this is Truman he came up with a brilliant plan, open to tell you the good news, the United States has just successfully bombed the atomic bomb, Stalin will no longer argue for the Black Sea outlet after listening to the demarcation of the Black Sea. Therefore, backed by the american atomic bomb, the Soviet Union was in a situation of looking out at the sea from afar and did not dare to really do anything.