Recently, the most unstable place in the world has been Ukraine.
On April 4, 1949, NATO was formally established, with 12 founding members (including the United States and Canada) at the beginning. NATO has a large number of nuclear weapons, conventional forces, and is in fact a military organization of the West. Before the end of the Cold War, NATO membership expanded to 16, adding Turkey, Greece, Spain, and Germany. After the collapse of the Soviet Union, NATO has been expanding eastward, and to this day there are 30 NATO members.
NATO's continuous northward expansion has put Russia under pressure and forced to make strategic adjustments, from being as soft as possible to the West to a thoroughly tough attitude. The game between NATO and Russia is also a continuation of the previous game between Western countries and the former Soviet Union. Russia's western border states, which are currently left with only Ukraine and Belarus, have not joined NATO, and until 2014, Ukraine had been oscillating between the West and pro-Russian, and in April 2014, due to the crimea incident, Ukraine accelerated its move closer to the West.
Once Ukraine joins NATO, the remaining Belarus is surrounded by NATO on three sides, coupled with economic sanctions and color revolutions, Belarus may not be able to resist joining NATO, if such a situation occurs, it is not the result that Russia wants. For the big powers, once the geographical buffer limit is lost, the peaceful development of the country will be threatened, so Ukraine must not join NATO, which is Russia's bottom line.
Ukraine has a population of 41.58 million people, 130 ethnic groups, Ukrainian 77.8%, Russian ethnic 17.3%, the east of the territory is pro-Russian west is pro-Western, these two factions are the two major forces in Ukraine, and there are constant conflicts between them. The Dnieper River, the mother river of Ukraine, flows south into the Black Sea and has 6 hydroelectric power stations on the river. 70% of Ukraine's land area is black land, accounting for 25% of the world's total, and the fertile black soil makes Ukraine the world's third largest grain exporter and the european granary. However, crude oil and natural gas resources in the territory are scarce, and 90% rely on imports. Russia, in turn, is Ukraine's oil exporter.
The main reason for Russia's time-controlled Crimea is to ensure the safety of the Russian Black Sea Fleet, whose task is to control the Turkish Strait and go out of the Mediterranean to deal with the US Navy's Sixth Fleet. If Ukraine joins NATO and Russia does not control Crimea, the Black Sea Fleet will be locked up and at a strategic disadvantage.
Therefore, Russia will not let Ukraine's plan to join NATO succeed.