There is one simple solution to the problem of terrorism: kill lots of people, of which some are certain to be terrorists. Choose a terrorist-rich area, and if you kill everybody within it, then you can be sure no terrorists will originate from there ever again. It's a cruel policy and also a stupid one, in that it's likely to create resentment outside the killing zone, which will generate more terror later. Of course you can enlarge the killing zone, create a desert, and call it peace, but you cannot do that indefinitely, and the costs to everybody rise hugely as your killing zone expands. Unfortunately, politicians, the military and the public want a simple solution, and the Tacitean desert approach seems to be the policy of choice in today's world. It's the 'too much, too late' option, which, arguably, has led to numerous devastating wars.
I have another idea. Let's recognise that there is no simple solution. That it's likely that only a combination of different approaches, varying with time and over geographical area, will work, and that our goal is a sustained period during which terror will not occur. There are initiatives now that can help achieve that goal, But they're not co-ordinated and are heavily outweighed by the reactive policies of governments under pressure to 'do something' when an outrage occurs. Almost all the incentives on offer are to those with a strong interest, conscious or not, in keeping conflict going. This means the military, the men of religion, the ideologues on all sides, and the millions of intimidated and frightened ordinary citizens.
We need to put in place a system of countervailing incentives; one that encourages diverse, adaptive approaches, and one that will reward people who oppose or undermine the interests that generate conflict. We should focus on the long term, so that our goal would not be undermined by policy changes or unconsidered reactions to outrages. One way of doing this would be by issuing Conflict Reduction Bonds. These could be backed by any combination of governments, non-governmental organizations, philanthropists and ordinary citizens, whose funds would reward the achievement of a sustained period of global (or regional) peace. Incentives under a bond regime would cascade down into all sorts of initiatives, glamorous or not, high level or low level, bottom up or top down, old-fashioned or innovative: efficiency in reducing the prospects of conflict would be the sole criterion for the allocation of funds. For more see this previous post, or my papers on applying the Social Policy Bond concept to conflict reduction.