Once they realize that the opposition has live ammo, better training, a true chain of command, and far superior weapons most will just shit their pants and go home. Having been in a war, they really don't want to see one up close. There is a reason for all the PTSD in former combat soldiers.
In reality though, might they? I don't really think they could overrun it, but I think they would put up a good fight simply because the government won't want to be seen bringing in tanks snd dropping bombs on US citizens. They will be using the least necessary force and I think would use the local police for as long as possible. Note: I am in no way a gun nut, and would only buy a gun if i had to protect myself from gun nut. Checkout the podcast It Could Happen Here, the last episode How the American people can beat the US military