President Assad and Mrs. al-Assad

Quote: Mintball "In asking what someone would suggest who has just said there should be no military intervention, you effectively suggest that you cannot see any other option.

I think that we – and other nations – should be very careful about what we consider.'"

Any action against a sovereign state is already extremely carefully considered (for many of the reasons you mention, and many others), regardless of the eventual, possibly unforeseen, outcome or of an often not fully informed public opinion. The hurdle with tyrants such as al-Assad is that the options are limited. Other despots have already proven they have no particular regard for the welfare of their populations and have no problem martyring them in the face of tough sanctions - is that fair on the civilian population? Political pressure only has limited influence; every nation on earth could be yelling at him to stop and he can ignore them. Whatever happens he'll have enough to keep his supporters and his army supplied and fed, and that's all that matters to him.

Quote: Mintball "I mentioned Iran
Yes, that a power vacuum will invariably be filled by the most aggressive and/or ruthless opportunist. And that what to all intents and purposes seems an entirely rational act of intervention at the time, can often later be condemned with the benefit of history.

Quote: Mintball "Look at Afghanistan for another example. So easy to look at the Taliban and say
Going into Afghanistan was bugger all to do with helping women. It was a direct result of 9/11 and the subsequent hunt for anyone and everyone associated with Al-Qaeda. That's the simple truth of it. All the supposed 'benefits' brought to the Afghan population are after the fact. The USA went after Al-Qaeda/Bin Laden with no exit strategy, and given what had just happened in New York as far as I'm concerned they were entitled to do so.

Quote: Mintball "Despots, tyrants, mass murderers...call them what you will. The West's attitude has always been along the lines of 'it's ok as long as they're our despots, tyrants and mass murderers.''"

You could say that of almost any nation. If a despot, tyrant, etc is perhaps favourable to a nation in terms of geopolitical support, trade, etc, and is doing no harm to said nation, why get snarled up in opposing them?

Quote: Mintball "In reference to the op, you therefore have to extend the question, adding 'how the hell do the Western politicians who put the tyrants in power, arming them to the teeth and selling them the intelligence and expertise to target and use those arms sleep at night?''"

If you read many memoirs of those involved in the few circumstances where this has actually occured, most of them express regret, but the common theme is, "it was the right thing to do AT THE TIME. How were we supposed to know what would come next?" As ever, hindsight is a wonderful thing.