What is the fundamental contradiction between Russia and Ukraine?

At present, the contradiction between Russia and Ukraine is escalating. Ukraine's oil and gas depend on Russia, and it is difficult for Ukraine to deepen contradictions. The fundamental contradiction lies in the interests of the two countries.

In the early days, Russia and Ukraine were very friendly countries, and they were also one of the joint countries of the Soviet Union at that time. However, after the disintegration of the Soviet Union, Ukraine also inherited a large number of Soviet military heritages, so Ukraine was also the fourth largest nuclear power and military power in the world at that time. However, because Ukraine reminded the United States and European countries that it had destroyed its own nuclear weapons and advanced military equipment and suddenly became a toothless tiger, there was no military threat of nuclear weapons to Ukraine, which largely made Ukraine's national strength not strong.

The fundamental contradiction between Russia and Ukraine is the contradiction of national interests. Because with poroshenko's coming to power, Ukraine is more inclined to the United States in diplomacy and clearly hopes to join NATO as soon as possible. But doing so will make Russia very uncomfortable. Undoubtedly, Ukraine's move has seriously damaged Russia's national interests, because once Ukraine really joins NATO, Russia's strategic pressure will increase sharply and its strategic space will be severely squeezed.

On the other hand, there is a fan-shaped grassland between Russia and Germany, which is narrow here in Germany and wide here in Russia. Therefore, during the war, the longer the eastward front, the more difficult the defensive deployment and the easier it is to advance westward. Therefore, if NATO's power develops eastward, it will be very unfavorable to Russia. Look at the border between Ukraine and Russia, which occupies a large part of Russia's eastern border. How could the Russians want to lose this buffer state?