America has shown it
can exert influence around the globe. It is pretty poor at judging when it
should. America can operate nearly everywhere but the cost is a long way from "impunity". In cases such as Afghanistan America even relies on Pakistan for the logistical train. Far from ideal and adds a massive cost.
Many other places America even struggles to project its will these days - such as Central and South America. Mainly because it is less a leader than a bully.
What the USA really should be doing is spending large sums of money on updating infrastructure at home rather than building then destroying it abroad.

Bookmarks