An 'insurgent' force that was never estimated to be larger than 15,000 individuals tied the entire U.S. military down in Iraq for almost a decade. When we finally withdrew from that campaign, we did so without achieving a true, unqualified victory.
Those 'insurgents' held out against the most advanced, most powerful military in the world, with little more than AK-47s and IEDs.
Should the American people ever be pushed to armed rebellion, the numbers of those who would stand and fight would dwarf the numbers of Iraqi insurgents by orders of magnitude. It was 3% in the (first) American Revolution. That percentage would be greater today. Perhaps as much as 10%, which equals a force of 30,000,000 armed and committed souls who would be fighting to protect and defend their homes, families, and their very way of life, from an evil that they believe is hell bent on obliterating every trace of their country.
There isn't a military force on the planet that can conquer a home grown force that large and so determined.
No man volunteers for a battle he thinks he cannot win.
And yet, people lose in war all the time.