Are active duty and national guard units interchangeable? Troops?

I think he is correct, the forces are inherently different. Unfortunately this is mostly manifest in the fact that the National Guard receives less training, has lax standards, etc. However, there is a school of thought that says the National Guard and Reserves (i.e. our 'citizen-soldiers') should have a different role, preparing for the next big war (WWIII, Korea pt. II) and that the Regular Army (professional soldiers) should be prepared for any combat contingency in which our country needs them, usually small wars, counterinsurgency, intervention, and the like. I tend to agree with that school of thought