There were in fact two very different kinds of Communism posing very different kinds of threats: hard Soviet Communism, driven in Europe by the Red Army, and Communism as it was manifested in the Third World, where it became a convenient instrument of anticolonial forces,

 From The Coldest Winter by David Halberstam.  Page 93

When the president had arrived back in Washington in the early evening of the twenty-fifth, he was met at the airport by Acheson, Secretary of Defense Louis Johnson, and Undersecretary of State James Webb. From the moment the three men joined Truman inside his limo, there was no doubt which way the play would go. “By God, I’m going to let them have it!” Truman said. Johnson quickly responded that he was with Truman. Webb said simply that Truman should look at some of the things the people at State had put together for him. They had multiple recommendations as early responses to the still fragmentary reports from Korea, all of which were bad: they wanted the president to authorize General MacArthur to give the South Koreans such arms as they needed; to use American air and sea power to cover evacuation procedures and to hold Korea’s ports, lest they fall to the North in the midst of an evacuation. At the same time, based on the president’s future decisions, they wanted the Joint Chiefs to come up with what was militarily necessary to stop the North Koreans. They wanted the Seventh Fleet to move into the Straits of Formosa to block any Communist Chinese assault on Taiwan (and also to stop Chiang from doing anything to provoke the new government on the mainland). In addition they believed the United States should initiate military aid programs to support the French in Indochina, and offer military aid to Burma and Thailand. When the limo reached Blair House, where the president was then staying, Webb, in a moment alone with Truman, made one other suggestion: that they consider separating the Taiwan and Korea decisions, especially since Washington intended to take the case of the North Korean invasion to the UN.

If a line was not being crossed on that day, it was most surely being blurred, and it was not necessarily only in Korea. In the years immediately after World War II, there were probably two main issues confronting the policymakers in Washington as they sought to deal with the destruction of the old order and other havoc created by the war. The first and most obvious and most immediate was the need to draw a line against Soviet expansionism in Europe. That was done with great skill and vision, but unfortunately partially at the expense of the other great issue of the era, one seemingly less immediate and more peripheral in terms of sheer power—how to “respond to the end of a colonial age, which found the nation’s greatest allies being challenged politically and sometimes militarily by their former colonial possessions. On the question of understanding the power of nationalism in the underdeveloped world, cloaked as it sometimes was in a covering of Communism, Washington’s record was significantly spottier. There were in fact two very different kinds of Communism posing very different kinds of threats: hard Soviet Communism, driven in Europe by the Red Army, and Communism as it was manifested in the Third World, where it became a convenient instrument of anticolonial forces, who often turned to Moscow (as in Indochina) for help after being rejected by Washington. Whatever else can be said about the North Korean attack, it was an old-fashioned border crossing; but in Indochina, which the United States now began to tie to both Korea and the larger confrontation in Europe, it was a pure colonial war.