As she revs up for her Circus tour's big return to the States, Britney Spears appeared in an evidently pre-taped segment on Late Show With David Letterman last night to present "The Top 10 Ways the World Would be Different if Britney Spears Were President." It felt more like Spears was campaigning on a "check out my bikini body" platform rather than "health care reform for all," but that probably didn't come as a shock to anyone — including Letterman, who read the topic and joked, "Whoa ... think about that." We are, Dave, we are. Highlights included "We would only invade fun places like Cabo," "Three words: Vice President Diddy" and the standout "Free pie for everybody." Watch the full clip after the jump and check out photos of Spears' sexy Circus show here.