I agree with Trump's argument that we as a nation have been taken advantage of with regard to peace keeping, but if we want to continue to have the only superpower arsenal in the world, we can't completely walk away either.
As for projecting military power, fly a dozen B52s over any third world shit-hole and the rats will scatter.
As for walking away, why don't you enlist and volunteer to go to Iraq and get your head blown off. There are over 5,000 DEAD Americans because we want to "bring "democracy" to the middle east." Screw that shit. I hope Trump seals our borders, stops international trade, and lets the rest of the planet starve for a few years.
I speak only for myself, but American power projection since the end of the Cold War has been much costlier than any perceived benefit to America. Our reward for protecting foreign kings has been thousands of killed, tens of thousands wounded, hundreds of billions borrowed, a burgeoning surveillance state and the continued erosion of our liberties.
American greatness was never from protecting foreign kings. Too many have lost sight of that.