Why doesn't America have a Prime Minister?

No. In the US the President is head of state and head of government. It is a totally different type of constitution.

The US has one head of government and head of state. they don't have the problems of a semi prersidential system where parliament and president are always fighting. also more stable. It is because when the US got independance the King was in charge, the PM was just a high up civil servant.

In Wasilla they had to hire a city manager because MZ sarah could not be mayor and run the managerial side of the job. The US has turned the job of President into a kingship.. unfortunately. EDIT: Well, there are some who might say that was the role of Cheney...though it is NOT set up that way. (by our Constitution)

The equivalent position is called, I beleive, House Majority Leader. The PM is the leader of the party with the most seats in the House of Commons (equivalent to your House of Reps). In countries like Canada or the UK, where the Queen is head of state, but only ceremonial, the power lies with the PM. In countries like France and Russia, the President's powers are much more circumscribed than in the US - but of course, weight of personality really determines the power of the position

We don't need another redundant government position. Why does Britain have a Queen? Nearly every other modern nation has eliminated Royal positions.

Bigger government? No. Only if the position you create is "completely", not just wages, paid for by a reduction of twice the "total" cost from all the other ones already there.

No. The President, is the Commander in Chief. There is no place for a Prime Minister although, there should be ! The United States and the presidential republics in Latin America, modeled on the U.S. system, in which the president directly exercises executive authority.

Surely the Vice President does the same job.