In such a world, the citizen soldier will simply provide target practice. Warfare could well be conducted by Renaissance-style mercenary units, condotierri like Executive Outcomes.
As a consequence, the political balance of power will veer sharply back towards the state and state power as amateur resistance to Terminators becomes inconcievable. On a practical level, the military power of the developed world vis a vis even the most powerful developing countries (India, Egypt, Indonesia, Argentina, etc) will become as dominant as it was in the day of the dreadnought and the Maxim gun.
Do you think that modern weapon systems would be in reach of private outfits? Remember the US Arm was looking at a personal weapons that cost $10K a pop... Imagine EO trying to afford a super tank, or the previously mentioned powered armor.