Earlier quoted context omitted.
It's one of the reasons the 2nd Amendment was written; to avoid tyrannical rule, and to allow the "peasants" (regular people) to revolt if a tyrant ever took power.
As a European I've always thought that this bit of US law has not aged all that well. Imagine a tyrant takes hold of the US armed forces and uses that to overthrow the rest of government so they can rule alone. The US armed forces have equipment going up to tanks, fighter jets, bombers, drones and nuclear weapons. A militia is going to struggle to field even heavy machine guns, let alone an air force. I doubt they'd…
At the end of the day, holding territory is hard. Look at how much trouble Americans have had subduing the Taliban in Afghanistan. The bombs, tanks, planes, etc., are largely useless in holding a city. Now, combine that with the fact that the US military is comprised of citizen soldiers, who would be in the position of fighting against their own communities.
It’s when a community is totally disarmed, and when the mere show of military force would force total capitulation without violence, that a citizen military could rationalize aiding tyranny.
It’s also worth pointing out that there are 50 governors who command national guards that have fighter planes and tanks and whatnot. In a real civil war, armed citizenry would likely be fighting alongside state forces.