The Heritage Foundation has published the first annual Index of Military Strength for 2015
The report’s in-depth analysis of global threats and consequent US ability to meet those threats concludes that U.S. armed forces are marginally capable of prevailing in fighting two regional conflicts at once.
We are facing threats from the Middle East, North Africa, China, Russia and we cannot possibly meet these threats according to this assessment.
The report analyzes: the capabilities of each branch of U.S. military service; the nature and severity of major regional threats they may be called upon to deal with; the environments (Europe, the Middle East and Asia) in which they would have to operate.
Europe is the most favorable operating environment. Syria and Iraq present serious concerns.