But people clamour for military interventions by democratic countries that actually have armed forces which are globally deployable. The US, the UK and France are unusual that they have such forces, most countries do not.
So at some junctures there is a clamour, then later it may even be criticised by the same people. Libya is a case in point, was it right for the UK and France to intervene in 2011 when there was an uprising? I don't know - but if Gaddafi had subsequently killed 100,000 people we'd be asking why we hadn't intervened.
And Syria; Cameron (leading a coalition) put a decision on intervention through Parliament. He and Clegg involved Ed Miliband in discussions about intervention prior to the debate. Cameron thought Miliband was going to support an intervention but got his MPs to vote against it and was accused of "playing politics". Without the UK other major players did not intervene either - so Russia filled the vacuum - was that a better outcome?
Not that long ago Nick Robinson interviewed Ed Miliband and asked about this. Miliband was tight-lipped about whether he'd made the right decision.