Instapundit had an interesting link to an interesting article about the Proliferation Security Initiative (PSI). Basically, it's an alliance of countries that, geographically-speaking, surround countries that are trying to make WMD (be they nuke, bio, or chem). These member countries then help to interdict shipments of materials necessary to make these weapons. It's all peaceful and non-violent (no cargo ship is going to try to fight an actual armed warship) and seems to be working.
If you want evidence, look to Libya. They've dismantled and sent a good portion of their nuke stuff to us, with the rest on the way. The next target? Iran - the Caspian Guard is being formed, with Azerbaijan and Kazakhstan as the first members.