Why an armed orbital platform creates a first-mover problem

Would the first state to deploy an orbital bombardment cruiser gain a decisive advantage?

Potentially yes: an armed orbital platform could attack rival launches and missile systems, which is precisely the kind of destabilising first-mover advantage that encourages arms control.

The proposed orbital cruiser creates a first-mover problem rather than a conventional fleet comparison. Once one state held an armed platform in orbit, it could try to destroy competing vehicles during ascent and prevent a rival force from forming. A laser outside the atmosphere would avoid atmospheric thermal-blooming problems and could engage ballistic missiles, while kinetic rods could threaten launch infrastructure. The thought experiment explains why the United States and Soviet Union had strong incentives to restrain military competition in space before either side gained a decisive advantage.