The idea of limiting communism to the areas already under soviet control is called

 CONTAINMENT

Futher details/context:

George F. Kennan is known for recommending the policy of containment.  Kennan was an American diplomat in Moscow after World War II.  In 1946, he sent what became known as "the long telegram" of his advice about what the USA needed to do about the Union of Soviet Socialist Republics (USSR).   In those days, everyone feared an ultimate confrontation between the USA and the USSR -- that the Cold War would someday explode into a massive heated conflict between the superpowers.  Kennan, in Moscow, had much foresight to see the internal problems the USSR had.  He advised not pushing the conflict too much, but instead just try to "contain" the Soviet Union and wait for their system to collapse under the weight of its own problems.  Kennan was right.  It took almost 50 years, but eventually the communist system in the USSR fell apart.  [The Union of Soviet Socialist Republics came to an end in 1991.]

on the morning of  july 21,  1861, general mcdowell ordered the  unionarmy to attack. it was on this hill that  confederate  colonel thomas jackson and his forces held back theunion  troops.

cjokvxdtjvv