A recent argument made by nuclear weapons supporters has been that the increase of terrorism means we need nuclear weapons. Personally I believe the opposite is true - an increase in acts of terrorism is precisely why nuclear weapons are adding to insecurity: you cannot use a 'deterrent' against an ideology that does not care who it destroys - including its own followers.
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.
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.