An excellent, but possibly fatally flawed analysis.
You are assuming the goal is not to destroy the United States.
It was obvious even before the ‘08 election that the goal was to destroy freedom, to destroy Western Civilization, and most of all to destroy this country, to turn it into a third-world socialist dungheap.
I am assuming that. I would assess that the goal of the left is a social and political transformation of the United States from a Constitutional republic into a socially just collectivist state run by what they would view as benevolent elites for the betterment of all mankind.
When you get right down to it, transformation is the goal of most of our enemies. Militant Islam would far prefer to conquer the U.S. and convert us at sword point rather than destroy us outright. Same goes for the left.