Why does popular democracy, as defined in the U.S. Constitution, contribute to long-term economic growth and political stability?

(a) It allows regular change in the structure of the government.
(b) It provides incentive to invest, innovate and invent.
(c) It permits the President of the U.S. to choose fiscal policies to advance
contemporary mercantilism.
(d) It transfers wealth from the extremely wealthy to the desperately poor.