The North American Union (NAU) is a theoretical economic and political continental union of Canada, Mexico and the United States, the three largest and most populous countries in North America. The concept is that of a superstate and is loosely based on the European Union, occasionally including a common currency called the Amero or the North American Dollar. A union of the North American continent, sometimes extending to Central and South America, has been the subject of academic concepts for over a century, as well as becoming a common trope in science fiction. One reason for the difficulty in realizing the concept is that individual developments in each region have failed to prioritize a larger union.Some form of union has been discussed or proposed in academic, business, and political