A show of American force in 1954 might have really slowed the march of especially the Chinese and Russian influence in Asia.
What Chinese and Russian influence in Asia? Far from the main tenet of the Domino Theory, the communist movements in East Asia are/were pretty independent and national in nature. They got nominal material support, but they definitely had their own characteristics. Today, even after we killed millions of their citizens, Vietnam would rather deal with us than China.
