'You can't fight for a cause! A cause is just a thing!' said Rincewind.
'Then we are fighting for the peasants,' said Butterfly. She'd backed away. Rincewind's anger was coming off him like steam.
'Oh? Have you ever met them?'
'I - have seen them.'
'Oh, good! And what is it you want to achieve?'
'A better life for the people,' said Butterfly coldly.
'You think you having some uprising and hanging a few people will do it? Well, I come from Ankh-Morpork and we've had more rebellions and civil wars than you've had ... lukewarm ducks' feet, and you know what? The rulers are still in charge! They always are!'
They smiled at him in polite and nervous incomprehension.
'Look,' he said, rubbing his forehead. 'All those people out in the fields, the water buffalo people . . . If you have a revolution it'll all be better for them, will it?'
'Of course,' said Butterfly. 'They will no longer be subject to the cruel and capricious whims of the Forbidden City.'
'Oh, that's good,' said Rincewind. 'So they'll sort of be in charge of themselves, will they?'
'Indeed,' said Lotus Blossom.
'By means of the People's Committee,' said Butterfly.
Rincewind pressed both hands to his head.
'My word,' he said. 'I don't know why, but I had this predictive flash!'
They looked impressed.
'I had this sudden feeling,' he went on, 'that there won't be all that many peasants on the People's Committee. In fact ... I get this kind of ... voice telling me that a lot of the People's Committee, correct me if I'm wrong, are standing in front of me right now?'
'Initially, of course,' said Butterfly. 'The peasants can't even read and write.'
'I expect they don't even know how to farm properly,' said Rincewind, gloomily. 'Not after doing it for only three or four thousand years.'
'We certainly believe that there are many improvements that could be made, yes,' said Butterfly. 'If we act collectively.'
'I bet they'll be really glad when you show them,' said Rincewind. [...] He wanted to say: how can you be so nice and yet so dumb? The best thing you can do with the peasants is leave them alone. Let them get on with it. When people who can read and write start fighting on behalf of people who can't, you just end up with another kind of stupidity. If you want to help them, build a big library or something somewhere and leave the door open.
Terry Pratchett, Interesting Times

The whole debate often reminds me of this passage. I think Terry captured the problem rather well: you can't drive out one dictator and force people you never met to lead themselves. I think the envasion should never have happened, but since it has, you can't retreat now. Too late...