"What country can preserve its liberties if their rulers are not warned from time to time that their people preserve the spirit of resistance. Let them take arms."
Thomas Jefferson to James Madison
The founding fathers wrote the second amendment with the intention of the citizens of America to protect their freedoms from any force that would try to take those freedoms away, whether it be an outside force or internal force. The American citizen may have to take up arms against their government and its military and should be equally equipped so the government doesn't have an unfair advantage.
"I ask, Sir, what is the militia? It is the whole people. To disarm the people is the best and most effectual way to enslave them."
George Mason
Co-author of the Second Amendment