but he wasn't happy about it. >> in the final analysis, it's their war. they're the ones that have to win it or lose it. we can help them, give them equipment. send our men out there as advisors. but they have to win it. the people of vietnam against the communists. >> kennedy felt that the united states had to draw a line against communist expansion but the soviets supported the north vietnam regime. we supported the south. >> it's what becomes known as the domino theory. if south vietnam falls, then all the rest of southeast asia laos, cambodia, the philippines, they might be defeated. >> as i believe i reported upon my return from previous visits, i'm very much encouraged by the progress the south vietnamese have been making and the assistance our forces have rendered to them. >> when vietnam started up, they believed that they so expertly