What would be the most effective way to invade Russia? lol :),

Build a base so high on the orbit that Russian military grade missiles cannot reach it. Have a small point defense cannon on the station that can shoot at the enormous missiles that could reach it and evade the debris by maneuvering.

Then threaten to stop some rocks on Russia if your demands are not met.

Coincidentally the entire United Nations with everyone working together as one big happy alliance – US, China, Russia, India, Pakistan, Japan, EU,… All of them combined could not defend from such a threat.

At the same time all of them combined couldn’t build such a base as it stands. No one has that kind of technology and know how. No one can build rockets that can deliver battlestation components to high orbit.

It would take several years with everyone working together to get started with a missile that could shoot down the station. People might try to build a giant laser but it wouldn’t be very effective at the range. Also whatever the people below were building they run the risk that it’s going to be seen and a rock is going to fall on them. And while they’re building it they have no protection.