Question

What is meant when critics accuse the united states of maintaining an informal empire? how exactly has the united states asserted its influence informally?

Answer 1

The concept of an Informal empire describes the spheres of influence which an empire may develop which can be said to translate into a measure of influence over a region or country because of the extension of commercial, strategic or military interests of the empire.  In these terms, given the great economic and military power the U.S. holds in the world, it can be described as an informal empire.  

Answer 2

When critics accuse the United States of maintaining an informal empire they are referring to the political, economic, military and cultural influence the United States exert on the world today, assuming that this country imposes its power in an imperialist way.

The US confirms its imperialist influence when it participates in the political, economic and civil issues of other countries, often taking the most important decision on these matters.