Yeah, because a bunch of untrained people with guns are going to be able to stand up to the military. Hate to be the bearer of bad news for the would freedom fghters in America, red dawn is a move and they would be wiped out before they even got any sort of resistance going. The reason that the "rebels" in afghanistan and iraq have been so successful is because they were trained and outfitted by highly skilled military personnel from various countries. If the American government were able to turn the military on the people, the people would be shit outta luck.
Not necessarily. The military itself is made up of citizens. Plenty of them would desert as they aren't really interested in shooting their friends and family. They would take their skills with them. There are plenty of mountains and desert and other inhospitable terrain with hiding spots where rebels could hole up for long periods of time. Small arms would be handy for random minor engagements with patrols, hunting for food and defending against wildlife. Obviously they're not going to take on tanks and jets with them but they're essential to guerrilla warfare and very helpful in wilderness survival.
Really it would just be a matter of surviving until the lack of supply and support from civilians kicked the military's feet right out from under them.
Everybody good, plenty of slaves for my robot colony?