What we need to do now is go further... to imagine, and then create, a world without war. With the hideous death-toll in Gaza, the chaos in Syria and Ukraine, the turmoil in Libya, that might seem a long way from the reality of 2014. But the important first step is to say "this is possible", and then to start to plan the actions needed to bring a peaceful world into being.
Why are we planning on spending £100 billion to renew a weapon system floating around in submarines off the coast of Scotland when it could completely destroy us and our climate, leaving radiation for years to come? If Britain chooses to renew Trident in 2016, this is ultimately the choice we will make.
A layer of our political elite still thinks that Britain's power and status can be secured by Cold War weapons. But others already understand that the challenges lie in climate change, hunger, injustice - and the asymmetrical warfare in varying forms that those problems will increasingly bring if unresolved. This is where the thinking of our political class needs to be.
Nuclear apocalypse has been avoided. Iran has agreed to curb its nuclear activity. That's what they tell us anyway. Let's not get ahead of ourselves; even if Iran's cooperation is genuine, world leaders and their Iranian counterparts are not about to hold hands, hug it out or start tweeting funny cat memes to each other.
The real test of the Geneva agreement will be whether it does mark a move away from the old failed model of military conflict and towards building long-term peace instead. Ultimately, though, this requires full transparency of all nuclear programmes by all countries, full international cooperation for the immediate elimination of all weapons of mass destruction and an end to future reliance on nuclear energy. Only then can we be sure that our hopes of a secure deal for the planet will be realized.
The real-politik of the region is that Israel has never posed a threat to Islam or Arab nationalism. It's the possible spread of democracy from Israel that Arab leaders have long feared. Shiite Iran, on the other hand, sees itself as leader of the mainly Sunni Islamic world and wants to take that honour away from the Saudis. Israel now seems a much lesser of two evils to the Saudi Royal Family...one that could help them curb Iran's ambitions.
Is it possible that inducing a psychological state of fear and paranoia is not just a side-effect, but indeed part of the tactical purpose behind deploying drones? What would be the longer term mental impact on us, if drones constantly circled overhead where we live, arbitrarily and randomly striking out people we knew, every now and then?
I can't help wondering what six Kurdish men currently facing execution in Ghezel Hesar Prison near Tehran might think of the praise being heaped on Rouhani? Like numerous other condemned prisoners in Iran, they face the gallows after being convicted of vaguely-worded offences, including "enmity against God" and "corruption on earth".
On Tuesday, the Liberal Democrat Conference will debate and vote on the future of Britain's nuclear weapons system. Putting this controversial issue out for open debate is much to the party's credit and its record on challenging the status quo on Trident is streets ahead of the two main Westminster parties, which remain mired in Cold war thinking.
Once again renewing Trident is in the news, so some time soon we can expect to hear politicians or commentators explain that Trident is necessary because off the threats from Iran or North Korea, or some other rogue regime. Unfortunately, this is a complete red herring of an argument as long as you've thought about the issue for a couple of minutes. And now I'm going to explain why.