What limits missiles launched from an orbiting spacecraft?

Which current power has a missile that could arm a spacecraft and engage a target while remaining in orbit?

The response favours the United States but names no missile. It discusses possible spacecraft platforms, then identifies thrust vectoring, short motor endurance, and target conditions as limits.

The response favours the United States and speculates about SpaceX systems and uncrewed military spaceplanes as possible platforms. Another participant points out that the question concerns the munition, while the reply continues discussing launch and recovery vehicles. High-atmosphere missile experience is offered as a reason for the American choice, but no particular missile is identified. A further answer says thrust vectoring would be needed. Short rocket-motor endurance would also restrict engagements to a close or otherwise favourable target. The exchange therefore suggests constraints and possible platforms without establishing an operational orbital weapon.