Military affinity is nothing new in American culture. To be sure, the Founders were obviously circumspect about it, as reflected in the prohibitions on quartering of troops and the separation of war powers among the legislature and executive.
I suppose if one had to point to where it took root, I'd probably go back to the populist Andy Jackson. Harrison of course ran his election on it. Then about two decades of post-civil war generals, TR, Ike, JFK, Bush, Carter, etc. And of course the emergence of political forces like the GAR, the VFW, SCV, American Legion, etc. And of course the military experience of WWII created a new socioeconomic confidence that filtered down to about 3 generations of people. More recently, a generation that stepped up after 9/11. With our history - both distant and recent - it should hardly come as a surprise that it's fertile ground for many things, including government spending and legal deference.
As to law enforcement, you're right that there's a federal v state dichotomy out there. Again, when did that arise? Each in their own way, I suppose you have to pin that on JEdgar and Bobby Kennedy. Personally I think Holder grew that capital in a material way, and it's continually eroded (as has he) since. Why is that? Well, I suspect he built it to focus on a particular type of crime, and now it's having to deal with very different types of crime that are, shall we say, less genteel.
The weird thing is, so many of the current putative abuses involve situations where congress has built the machine, and worse yet, granted broad discretion to operate it. i do hope that in the next decade there is a very hard look at our authorizations and spending with a historical eye to our recent experience.