Not anymore. That was true for the post WWII thru Vietnam eras. But when Clinton restructured the military to peel away money for his social programs they put the majority of the country's combat punch into the national guard and reserve systems. I lost track of the number of deployments the FL National Guard has had to either Iraq or Afghanistan. The state guards have been battle tested and emerged as steel. They can't be denigrated as Weekend Warriors ever again.
Now, as to whether they will obey orders that inflict direct harm to American citizens, I dunno for certain but I think they will, mostly. About 75% to 85% will act against the populace. Here is why: They are mostly products of the public schools and have the same limitations in their educational backgrounds. There is a reason for the "dumbing down" in school. If you never learn the truth about the Constitution or the Bill of Rights, you're less likely to wish to lay down your life protecting something you never learned and don't understand. We have bred our children into liberal sheep who will follow orders like good little lemmings, no matter what the cost to freedom. There is significant information to support this theory. Case studies going back generations, too.
RE: “the dumbing down”: Well said - And a very valid point... unfortunately.
Sadly, this freeper must note you are all too correct. The populace has been dumbed down and degeneracy has been defined down so far that most young people do not see anything as truly degenerate on their sliding scale of morality. With such a people our Constitutional Republic type of government cannot survive. And we see it dying before our very eyes!
About 75% to 85% will act against the populace.
BS
“That was true for the post WWII thru Vietnam eras.”
That is nonsense too, the Guard and Reserves still had to attend the regular process to become whatever their title was, fighter pilots were fighter pilots and Airborne Ranger LRRPs were still Airborne Ranger LRRPs.