Why did the u. s the french in their fight against hochiminh?

The US was certainly anticommunist and certainly a French ally but it is described in Bernard Fall's "Hell in a Very Small Place" as a gradual process.

the dominoes began to fall. the surrender at appomattox took place a week later on april 9. while it was the most significant surrender to take place during the civil war, gen. robert e. lee, the confederacy's most respected commander, surrendered only his army of northern virginia to union gen. ulysses s. grant

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