There's a reason why real power in the U.N. resides in the Security Council, not in the General Assembly.
Jacksonian democracy is indeed a good example to illustrate our point.
BTW, it seems significant that during the presidential campaigns this time, foreign policy hardly became a subject of debate. To elaborate on the relation between domestic democracy and imperialism, we might also consider how the nature of the military, the character of wars fought, etc. make a difference in the degree of domestic democracy necessary for securing citizens' consent to imperialism.