[krapp]

Simple Prisoner's Dilemma - you know that the other nations have signed a treaty against militarizing space, but why would you take anyone else at their word?

The answer is, you don't - you try as hard to militarize the hell out of space before anyone else, because you assume everyone else is doing the same.

[sbaoufbasfub]

The other answer is like the Nuclear Non-proliferation treaty and START I,II. Intrusive verification by international bodies with penalties for non-compliance. It hasn't been perfect, but so far the world hasn't ended.

[sbaoufbasfub]

Sorry by START II, I meant New Start. START II was cancelled before it went into effect in retaliation for George W. Bush cancelling the anti-ballistic missile (ABM) treaty.