We are a loooooong way from having to take up arms against our government. Mostly because our law enforcement, especially at the county sheriff level, and military understand they are fighting for the safety and freedom of law-abiding citizens. They've sworn to protect and uphold the constitution and are putting their lives on the line to do so.
What are the chances those very people would obey an unconstitutional order from any president to seize power? If a president was dumb enough to try overthrowing the democratic process, disarming the American people and installing a military dictatorship, I believe most if not all of the military and law enforcement of this country would either refuse or be fighting on the side of freedom because that's exactly what they signed up to do.
And an armed citizenry stands as a final check against tyranny, but we don't surrender that power just because we may not need it today. How the heck do we expect to be treated equally by those who are willing to use force against us if we are not prepared to use force in return to protect ourselves? That doesn't mean we aren't civilized, just that we are realistic about the nature of man.
In a perfect world everyone would play nice and then, maybe, we could disarm ourselves. Even then, I'd still want to target shoot and go hunting.