DAKOTA WOOD, Senior Research Fellow for Defense Programs, The Heritage Foundation, Editor, annual "Index of U.S. Military Strength," retired Lieutenant Colonel, US Marine Corps: 

Part I: 

Do all US allies live up to their expectations when threatened with conflict? 

Why are operating conditions more favorable in Europe than other parts of the world? 

Part II: 

Why is China characterized as an "aggressive" but not a "hostile" threat? 

Over the past year, the People's Liberation Army, Air Force and Navy have been upgrading and enlarging their power projection techniques

Dakota Wood: The index's recommendation that the US Army consist of 50 brigades is seriously lacking

Part III: 

Average age of a US fighter jet is 30 years old

Under the Trump Administration, the Department of Defense increased flight hours in order to ramp up force readiness

Overtime, the number of US Marine brigades have shrunk as the branch embraces a "one war force" mentality

Part IV: 

The index categorizes most of the US nuclear force as strong. Why?

Wood: Many of the same politicians who are staunch opponents of the 2nd Amendment and advocate for increased public safety are now questioning the loyalty of National Guard troops