In the late 60s. The socialist camp experienced a deep internal political and ideological crisis caused by the split of the world communist movement (the opposition of China and the USSR) and the isolation of a number of countries in Eastern Europe. Communist regimes in Yugoslavia and Albania actually fell out of the world socialist system, having for a long time had their own point of view on the development of socialism. In Yugoslavia, the course was taken for the construction of a special popular socialism, and in Albania there was a conservation of the Stalinist model. The position of the GDR, whose state status and borders were not recognized by many of the leading Western countries, was still uncertain. Certain contradictions in the economic policy of the CMEA existed between Romania and the USSR. Bucharest did not like Moscow’s allotment of a raw material partner.

The rejection of the old Stalinist model of socialism inevitably led to the search for new ways of developing the socialist system, which was most clearly manifested in the reform reforms in Czechoslovakia, Poland and Hungary in the second half of the 1960s. Economic and political reforms in these countries initiated a new course of the Soviet leadership, which carried out similar, though more cautious, transformations in the USSR. Meanwhile, it soon became clear that the parameters of economic reforms in Czechoslovakia far exceeded the limited framework in which reforms developed in the USSR. The leadership of the Soviet Union was also disturbed by the fact that the reforms in Czechoslovakia were accompanied by certain political changes, an increase in the role of the intelligentsia. In the very Czechoslovak Socialist Republic in the summer and autumn of 1967, there was an economic decline in the rate of production. The economic crisis was due to inertia of management structures. Foreign policy differences on the question of a peaceful settlement in the Middle East reinforced the negative perception of the communist leadership. The government of Czechoslovakia supported the Soviet Union in its pro-Arab position during the Arab-Israeli war of 1967, while the majority of the Czech intelligentsia rather sympathized with the Jewish side. This, along with the aggravated contradictions between the Czechs and Slovaks (the latter were almost not represented in the leadership of the country and the party), turned into actions against the communist government.

Trying to prevent such a development of events, the Soviet leadership recommended that the Czechoslovak Communist Party commence personnel changes in the governing bodies of the party and the country. Cech Novotny as party secretary general was replaced by the Slovak Dubcek, who proclaimed a policy of building "socialism with a human face". In April 1968, the Czechoslovak Socialist Republic adopted a program of actions for the new leadership, providing for the government by the right of public confidence and the democratization of the economic and political life of society, the abolition of censorship restrictions. Initially, these changes were accepted in the USSR with approval. However, the development of events in Czechoslovakia and neighboring countries soon changed the point of view of Moscow. The atmosphere of glasnost, characteristic of the Prague Spring in 1968, turned into an increasing number of anti-communist speeches, rallies — the ruling party was losing control over the political processes in Czechoslovakia.

The support of the opposition from Western countries also contributed to this.

In March 1968, under the influence of Czech reforms, mass demonstrations took place at the University of Warsaw. The leadership of Poland, which suppressed the student movement, spoke in favor of changing the attitude of the socialist countries to reforms in Czechoslovakia. A similar proposal was made by the leadership of the GDR, which, among other things, secured the signing of the treaty on borders with Germany by the Czechoslovak Socialist Republic. In the summer of 1968, the leadership of the USSR was inclined towards the force version of resolving the crisis situation. On August 21, troops of the USSR, Poland, GDR, Hungary and Bulgaria were brought into Czechoslovakia. With the introduction of troops, 11 soldiers of the Soviet army died, another 85 died as a result of accidents, injuries, accidents and diseases. Instead of A. Dubcek, the general secretary of the Communist Party of Czechoslovakia was appointed A. Gusak, and the reforms carried out were curtailed. The loss of the civilian population of Czechoslovakia in the period from August 21 to December 17, 1968 amounted to 94 people, another 345 people were injured. Subsequently, on December 5, 1989, the Statement of the Soviet Government and the Statement of the leaders of Bulgaria, Hungary, the GDR, Poland and the USSR were published, in which the introduction of troops into Czechoslovakia in 1968 qualified as an unlawful act of interfering in the internal affairs of a sovereign country. the process of democratic renewal of Czechoslovakia and had lasting negative consequences.

The introduction of troops in Czechoslovakia intensified the split among the socialist countries. China, Romania, Yugoslavia and Albania (left August 1968 from the Department of Internal Affairs) became even more distant from the USSR. The Communists of Western European countries criticized the actions of the Soviet Union. Particularly acute was the reaction of China, which accused the USSR of imperialist politics, at the same time, however, speaking out against the "Czech democratization". The relations of the USSR and China acquired an increasingly confrontational character and in 1969 turned into an armed confrontation in the border regions of the two countries.

From March 2 to March 21, 1969, military operations were conducted in the area of ​​Damansky Island (300 km south of Khabarovsk), for which China presented territorial claims. As a result of coordinated actions of border troops and units of the Far Eastern Military District, the border was restored. The loss of personnel of the Soviet troops amounted to 58 people dead, 94 wounded. On August 13, 1969, Soviet border guards repulsed a new armed provocation near Lake Zhalanashkol in Kazakhstan, killing two Soviet soldiers. The great losses suffered by China in these conflicts forced him to abandon the use of force to resolve disputed territorial issues. However, ten years later (in 1979), China will attempt to resolve the Vietnamese-Chinese contradictions by war.

The USSR supported Vietnam, which in the course of three-week military operations defeated the "border" troops of China. The losses of the latter amounted to 62.5 thousand killed and wounded, 550 military vehicles (including 280 tanks). The settlement of relations between the USSR and China occurred only during the period of perestroika. In the 70s, the Soviet Union was forced to spend 200 billion rubles to strengthen its border and the PRC. The crisis situation developed in the early 70s. in Poland, where by this time the collapse of economic reforms was fully revealed. The government tried to suppress the mass strikes of workers in 1970 in Gdansk with the help of the troops. As a result, the entire Baltic coast was covered by the strike movement, sometimes taking on armed forms of resistance to the authorities.

The Soviet government did not dare to re-use (after Czechoslovakia) the use of troops stationed in Poland, and recommended that the Polish leadership find a compromise solution. The Polish United Workers Party (PUWP) was proclaimed by E. Gierek (worker by birth), who managed to bring the situation in the country under control. Poland received large international loans, which allowed to reduce social discontent, as well as to make partial re-equipment of industrial equipment. However, the bet on the import of products did not justify itself, by the beginning of the 80s. an economic crisis has reappeared in Poland. The confrontation between the authorities and the opposition (Solidarity trade union) ended with the appointment of General V. Jaruzelski to the post of PUWP chairman, who introduced martial law in Poland in 1981, banning the opposition movement (canceled in 1983).

Considering the results of the Czechoslovak events of 1968, the Soviet leadership in the early 70s. formulated a new concept of relations between the countries of the socialist camp, the emphasis in which was placed on protection against any encroachments from inside and outside the socialist system of Eastern European countries, up to the provision of international assistance by the Soviet Union (the so-called Brezhnev Doctrine). Eastern European socialist countries were again placed in a subordinate position in relation to the USSR, which was fixed by the presence of Soviet troops on the territory of Hungary, Poland, Czechoslovakia and the GDR. Bulgaria and Romania, where there were no Soviet units, were integrated (like the countries mentioned above) into the CMEA system, closed to the USSR. By the mid 70s. with the help of these measures, the relative unity of the social block was again achieved