According to immanuel wallerstein's analysis, the united states is considered at the whereas neighboring mexico remains on the semiperiphery of the world economic system.

I believe the answer is: Core

A nations is considered as a core of world's economic system if every economic decisions that made by that country would most likely set up the economic trend for the rest of the world. Other example of nations that considered as a 'core' are: England, China, Russia, and Germany

Abortion would be the most interesting topic to me