How do you defeat a populace that is armed to the teeth?
Convince them that the earth is dying from overpopulation so that they stop breeding. Replace them quietly. Make them pay for it all.
Their leaders can be blackmailed and they can be bought. Install your own people and rob them blind while they they are all fixated on the lies that flood from the places like their televisions and phones. You know, those places that they are all desperately turning to for the truth.
Make sure that everywhere they look is more lies. Poison them all slowly, too. Make sure it's slow enough to always allow room for our carefully crafted narrative to develop around something else to blame.
We will put it all in the "facts and figures." But then we will make sure none of them know how to understand it. The scientists all work for whoever has the money. And we are robbing those people in the trillions.
But we need to be so much worse than that. We will deny them the ability to reason. We will place all their children into workforce indoctrination systems so that they may enter the workforce and toil their life away being profited off of and heavily taxed. We will deny them the ability to identify and utilize the key components necessary to defend their own minds.
They will feel it. They will know that something is terribly wrong. But no one will be able to explain it. No one will have the means to articulate the truth, much less argue the case before the world. If such a person does arise. Just kill them and usurp their identity via their cherished protégé.
They have no chance. They are already lost. Sure, they'll have their guns. There just won't be any them left. We will make them fight each other.
It's time for you to wake up.