It's debatable as to whether you could technically call the Bush (or Kennedy, or any other) family a "dynasty". After all, the definition is simply that of a succession of rulers who are members of the same family (though if you want to be pedantic, Clinton's interlude precludes their being a presidential dynasty). Thus, just because a series of family members are in political offices, they aren't a 'dynasty'. That would require the passing of a specific office from father to son - which COULD have happened had Bush the Elder passed the office directly to Bush the Junior.

Now if you want to state that the Bush, Kennedy etc. families represent an unhealthy amount of political offices held by a given family, I'm with you on that.

M