LONDON: Ten years ago the leaders of Britain and America took their countries in to wars in Afghanistan and Iraq fuelled by a messianic certainty about their ability to transform the world as they wished. Both George Bush and Tony Blair presided over countries with their own intractable problems — pockets of joblessness, drugs, gangs, inequality — but they combined an inability to solve these domestic issues with an insouciant confidence that, somehow, the problems of Far Away were simpler, and could definitely be sorted out swiftly by several thousand chaps with missiles and guns.

We have all learned how miserably, catastrophically wrong they were. What marks the proposed action against Syria is the weary, wary attitude of the people who feel they are now obliged to enter it. There are no fantasies about the smooth creation of harmonious democracies — only a grim sense that every other option has been exhausted, and that leaving tyrants free to break international rules with impunity will be more dangerous than anything that’s gone before.

I wanted something more than this. Like millions of people, I was appalled by the Bush/Blair fairytale version of the world, in which it was possible to identify the good guys, punish the bad ones, and leave everyone living happily ever after. But I have been clinging to my own fairytale, which is that somewhere in the world there are wise people who do understand the complexity of what’s going on, can plan constructively and cautiously for acting on it, and can reassure us that they understand what’s coming next. That’s why I thought Britain’s Labour party leader Ed Miliband was correct to urge proof, caution and a roadmap before sanctioning any military action last week.

Unfortunately it turns out that there are no wizards behind the curtain. The smart, thoughtful, well-intentioned people running America’s policy behind the scenes are bleakly aware that they have been proved wrong so far. They offer no certainties about the future.

The west went into Iraq and Afghanistan without planning for what might happen next. The Obama administration resolved never to make the same mistake. The state department and the military have spent the past two years obsessively modelling what various interventions or non-interventions in Syria might achieve. The problem is that nothing has developed as they expected, and every projection has left them, as one thoughtful observer says, “down a different rabbit hole”.

Leaving refugees to flee the country is putting intolerable pressure on Syria’s neighbours. At any time one of those countries might decide they have had enough, and shut the border. Locking refugees inside Syria creates a whole new set of problems. If the international community wanted to defend them, no-fly zones wouldn’t be enough. Safe zones would mean ground troops, who would instantly be seen as an occupying army — and no one in America wants to take that route again.

Attempting to concentrate on the west’s strategic priorities — the securing of Bashar al-Assad’s chemical and biological weapons so that neither he nor any rebel groups can use them — would be no easier. This isn’t a James Bond spy film situation, where a small team could fly in and secure a single threatening facility.

The WMD sites are scattered across the country, and consist of tonnes of material. Getting the weapons out would take months. The foreign troops doing the job would have to be protected and supplied in a hostile environment. America has spent a year, and more than GBP40m, training Jordanian troops to do exactly this, but intense conflict would be inevitable.

The west’s preferred option — to fund and advise the moderate elements of the Syrian opposition, in order that they could win their own war — hasn’t worked out either. Almost every expert on the region expected Assad to have been overthrown long ago. Instead the arms and aid he’s had from Russia and Iran have tipped the balance in his favour, while the west’s favoured rebels may have been outnumbered by the radical and Al Qaeda factions, assisted by fighters from Turkey, Syria and Iraq.

Western strategists involved feel it’s like playing four-dimensional chess in real time. Day to day, they’ve watched, waited, and taken what seems to be the right decisions only to end up in a morally indefensible place. Now they feel an unbearable line has been crossed. But they know that every action has terrible endings, as it has done for 18 months.They aren’t certain who the west’s good guys might be. As to what’s going to happen on “action day plus one”, they say bleakly that even though they have been thinking about it for two years, knowing that is beyond them. It’s a Shakespearean dilemma. Sometimes the least bad option is the only one.

The unpalatable truth is that there is no safe, morally pure solution. Watching and deploring has its own appalling consequences. Paralysis leaves Assad free to poison as he likes, while threatening to attack him might erode his support and force him to negotiate. Everyone wants a diplomatic solution: the disagreement is about how to get there.

I have reluctantly concluded that Obama’s conviction — that the world must not rule out military action — is right. But there can be no fairytale endings, only hazardous choices, and more deaths.

By arrangement with the Guardian