The issue of dual use has been most prevalent with the Iranian nuclear issue. (time line here) The argument from the Iranian perspective is that nuclear material, fuel, and power is needed to bolster a petrol based economy that is faltering and doesn't provide cheap energy for all. Adding to this argument is that Iranian heavily subsidizes its refined petroleum products. Subsidizing in this case being the refined product that Iran should be able to produce internally is imported. Years of sanctions has destroyed Iran's ability to refine and lessened its ability to draw oil out of the ground. So Iran sells a limited supply of oil to import gas at a higher price, essentially an economically losing position. In terms of the Iranian logic in order to offset these heavy energy costs they need to develop a more efficient system of energy production, thus the need of nuclear energy.
On the one hand Iran signed the NPT and is guaranteed access to nuclear power. On the other hand the issue since the Shah's time has been that Iran is diverting fuel and technology to a weapons program. And this diversion has been taking place since the Shah's time. This issue has sharpened greatly post 9/11 with Iran being placed squarely in the Axis of Evil for its support of terrorism.
The issue becomes sharpest when the president of Iran, Mahmoud Ahmadinejad with the tacit consent of the supreme leader, Ayatollah Ali Khamenei begins to develop a stronger missile and nuclear program. Factor in some of the more controversial statements made by Ahmadinejad and the question remains: Does Iran aspire to be a responsible nuclear power or a belligerent?
The other issue is the idea of modification. This is the idea of taking an existing technology and changing or modifying in such a way that it amplifies the damage of that particular weapon system. Damage, in this case, being the nuclear level.
I think this story best exemplifies what I'm talking about. Since the eighties and then after 9/11 the United States has been transferring arms and technology to Pakistan first for defeating the Soviets then to fight the insurgency in Afghanistan and al-Qaeda. Pakistan also has preexisting nuclear program and a very dangerous rivalry with India. Pakistan uses the missiles acquired from the United States changes the war head from a conventional to a nuclear, and presto a nuclear missile.
The over arching theme here is the flow and use of information and the self-interest of states. On the one hand it is difficult to progress scientifically and develop beneficial technology without the free flow of ideas and information. But on the other there is the self interest and competition among states. It would seem that the context of competition shapes the science. And the science shapes the competition. Interesting equilibrium.