Is this to imply that a country has nothing to gain by going to war with another country? Obviously not, war costs billions, and the US wasn't directly (or argu

Is this to imply that a country has nothing to gain by going to war with another country? Obviously not, war costs billions, and the US wasn't directly (or arguably indirectly) under threat from vietnam, so there wasn't any reason to engage in war unless they had something to gain (or fear losing, which seems just as bad). Going by the logic that the US had something to gain in engaging with war in Vietnam, or any of the other many places they've done so, it stands to reason that future presidents would benefit from it. Maybe not in extracted wealth, but to say anything goes unless its directly earning money from it seems a bit odd.