If you have the ability to deflect an asteroid away from an Earth collision, you have the power to aim one at Earth.
I’m OK with that as long as I’m the one in charge of that capability.
Who would you give that power to?
considering that the US is both functionally broke/bankrupt AND trying to end the space program, I would put China high on the list of countries with orbital or moon-based space warfare capabilities in 20 years.