Historically, when the Constitution was written (and the 2nd Amendement was enshrined therein), there were no police to call and there was no standing army. The citizens were expected to: 1st) defend themselves, and 2nd) be ready to constitute a militia to defend the common good. That especially included tyranny from external sources.

Now we have a standing army to defend ourselves from external organized attack. Now we have police who will slowly respond to personal threats. Slowly is important here. They respond slowly. If they are called to a violent event it's usually all over by the time they get there. Then they fill out some forms, take a few statements and clean up the carnage.

Now, especially on the Internet, we see the local police have become populated with a certain number of sociopaths and psychopaths. Some are drunk on power and they are armed to the teeth. These head cases might well run totally amok if they are the only ones armed. The widely available arms keep these psychos in line to a great extent.

When people talk about the "right to keep and bear arms" as envisioned by the founding fathers, they often refer to keeping tyrannical government in check. This is usually framed as keeping the national government in check, but since the fathers also created a decentralized form of government (national, state, County) they must also have envisioned that the populace could use these weapons to keep government in check at all levels, i.e. "foreign AND domestic."

When the Constitution was drafted, each state was considered a foreign country bound by a contract to provide for the common defense and to regulate commerce between said states. Since each state is "foreign" to the others, the right to keep and bear arms could also apply to one state against another, as strange as that seems to us now.

So, first and foremost the guns keep us safe from each other, secondarily against a rotten government and thirdly against foreign invasion.

I agree with some of the other posters when they say that "gun control" is now synonymous with total banning of all firearms for the populace.

"An armed society is a polite society."