The people never matter and the oppressed masses never matter. What we always have is some quite small powerful conspiratorial group, which has a great deal of power but lacks legitimacy, moving against legitimate and traditional power, and invoking the masses as mascots.
I don’t disagree with Jim’s contention that one of the main long-term drivers of the political collapse of ancien régime states was the replacement of feudal magnates by civil servants. I’ve gone into that in some detail here and here. But just as there is an unavoidable tradeoff between the risks of entrusting high office to aristocrats and the disease of bureaucracy, so too there is an unavoidable tradeoff in military affairs between mercenaries and militia.
The basic question is simple. If a garrison is ordered by its officers to shoot into a mob of unarmed commoners, will they? If they definitely will, they are reliable and “good soldiers”, but they’re ultimately loyal to their officers. If they sometimes won’t, the locals will probably think of them as “patriots” but they’re like dry twigs, waiting for a spark.
If soldiers are perfectly happy to gun down unarmed rascals, they’re probably happy to mistreat them in other ways… especially where there is the prospect of plunder or pleasure. And if they’re happy to harm their country men under orders, they probably don’t need much of an excuse to harm them without orders either, so long as there is no chance of getting disciplined.
Now, generally they will get disciplined, because officers like to lead well-oiled fighting machines and nothing wears down a machine faster than a descent into petty crime and rape-orgies. But officers also know the value of rewarding their subordinates for a job well done, so, historically speaking, they are not averse to intense, targeted pillaging, either as a bribe before a difficult undertaking or as a reward after a hard-fought success.
This can be a headache for the sovereign. The smaller headache is that, in addition to having officers to keep the troops disciplined, he needs some way to keep the officers disciplined, lest they extract goods and services from the population they protect (a line of business which the sovereign must guard jealously). And again, there is a trade-off between two options: either the officers behave because they have colonels who keep them in line, or they behave because they would never dream of hurting their innocent neighbors anyway.
You can see the ugly principal-agent problem this is setting up. Bottom line is, you can protect a state with armies filled with recruits who don’t give two shits about their neighbors. You can also protect it with foreign mercenaries. Heck, you can even invite in a whole nation of Goths to bulk up your legions: worked for Marcian, didn’t it? But ultimately the only reason these troops can keep order is that they do whatever their officers tell them to. And sometimes their officers tell them to rebel; so they rebel (yes, “whatever” means whatever); and there is a lot of slaughter.
Anticipating this problem, many sovereigns prefer soldiers who are, to some degree, loyal to their side, not to their officers. Sure, they’ll obey the officer so long as they perceive his orders to be motivated by loyalty, discipline, and honor, but they melt away when he tries to use them as pawns in a personal power struggle. (Or frag him.)
Getting a soldier to think of his countrymen as friends and foreigners as foes is complicated. Lots of different techniques. Bottom line is, it solves the revolt problem but now you care about how big the angry mobs are. A little angry mob, okay, no problem. They’re not going to want to get too close to the bayonets. A big angry mob… well, you’ll have to cross your fingers and hope the regiment follows its orders. This time.