Resolved: Unilateral military force by the United States is justified to prevent nuclear proliferation.

Nuclear Proliferation - according to the US Legal Dictionary, is a term used to describe the spread of nuclear weapons and weapons-applicable nuclear technology and information.
United States- Territories and her allies

Contention 1: The threat of nuclear weapons falling into the hands of rogue states and terrorists increases as more countries possess them.
Example A: Selling to militant groups and/or countries with intentions to use nuclear weapons.
Starting in the 1970s, Pakistan used extensive clandestine procurement networks to get technology for its own nuclear weapons program. Former Pakistani nuclear scientist A. Q. Khan directed the procurement [of Pakistani nukes] and used a similar network [as used to obtain Pakistani nuclear information] to supply Libya, North Korea, and Iran with designs and materials related to uranium enrichment for profit.(http://www.fas.org/sgp/crs/nuke/RL34248.pdf)
This is an example of what happens when action is not taken against the countries who are in possession of nuclear technology, whether they are showing signs of imminent threat or not. Every time nuclear information is distributed it increases the number of people receiving that information, in turn causing nuclear proliferation. The United States is justified to prevent this action that causes proliferation because the mere existence of nuclear technology poses a threat to United States citizens.
Example B: We cannot wait to be attacked on a nuclear scale, therefore preemptive measures are justified.
If the United States doesn’t interfere right now and stop nuclear proliferation, there could be the risk of terrorist acquiring nuclear weapons from countries, or worse, stealing them. This in itself is nuclear proliferation; the spread of nuclear weapons