> is just as important to it's success. Yes, but this is why I said the things I mentioned were 'pretty major additions', not 'the only reasons'. The Louisiana

> is just as important to it's success. Yes, but this is why I said the things I mentioned were 'pretty major additions', not 'the only reasons'. The Louisiana Purchase is routinely ignored in things like this, for example - with no Purchase, there's no Mexican-American war, no Texas or California, no Great Plains, no Mississippi trade, and France as a (friendly) neighbour.