The current technology (drones) has made it difficult to hide their ongoing practice of eradicating anyone who stands in opposition. They also know that this will lead to either, complete control (likely), WW III, or both.
Either way it will allow them to implement martial law (perhaps globally) for our own protection of course.
"The enemy" (anyone who resists) has already (conveniently) captured a few drones and can reverse engineer all that they want to(it wouldn't surprise me if "we" covertly pay for this).
When drone attacks reach our shores (which should be soon), then of course, martial law will become necessary. Mass incarcerations for all who resist. Bechtel, Halliburton, etc.. will get massive, "cost plus" contracts to build (more) detention camps. Slave labor will produce all that is needed for those not incarcerated.
A new era of complete world dominance will be born. Our masters and the necessary administrators will have complete control. Just imagine Nazi Germany on a world scale.
Just another conspiracy theory....
Fear is the enemy of freedom.