As low-Earth orbit is developed by government and industry, there is no technical reason that a spacefaring nation cannot launch dormant satellite killers that remain in orbit until called upon to target and destroy opposing infrastructure. If you can launch a satellite-repairing spacecraft, you can launch a satellite-destroying spacecraft. Satellites aren’t reinforced with hull plating. They are delicate and vulnerable by necessity; it is very expensive to launch anything heavy.
In a wartime situation, a Space Force would likely be called upon to cripple opposing satellites using a mix of such space-based assets and cyber attacks. Already, both the United States and China have proven they can destroy spacecraft when they so choose. In 2007, China blew up one of its weather satellites using an Earth-launched missile, to send a message to U.S. policymakers: Look what we could do if we wanted. In 2008, the U.S. launched a missile and destroyed a reconnaissance satellite of its own. The message to China: We can do that too.
The Outer Space Treaty forbids offensive operations in space, though doesn’t necessarily conflict with a prospective Space Force.