If space became unilaterally militarized, it seems to me that it would be relatively easy and inexpensive to minimize or eliminate that threat if one were a country with a mind to.

Don't know how technically feasible this is, but on the surface it seems possible to send up a whole bunch of "shotguns", vehicles just filled with small bits of mass, and pollute the area. Geosynchronous orbit would seem to be especially vulnerable.

The "pellets" would be large enough to do damage, small enough to be difficult to track on radar, unguided, and have some velocity.

That might not eliminate the threats immediately, or in a week or month, but might make space too unreliable as a neighborhood to spend billions on a vehicle which might not be functional in a couple of days.

Sort of the "if I can't have it no one will" idea.

Don't know how cost-effective that would be, but it is simple.

Arf