In the 2012 remake, they're North Koreans.
Either way, this local event represents a nationwide security failure: the baddies have invaded the US mainland. A crack team of high-school kids fades into the mountain country around the school to form The Resistance.
In time, the kids' immediate grasp of bomb-making and other sabotage techniques; their commitment to arguing face-to-face about their relationship issues; their adherence to American Values and clean laundry are so effective that the nasty Russians roll over to have their tummies tickled.
Or something like that. The 1984 Red Dawn runs for 114 minutes.
In the 2024 film Capitol, a group of middle-aged American citizens in fancy dress invade the seat of democracy in the USA. Shots are fired; there are deaths; the invaders describe their action as a "coup" and then split up either to go home or do some sight-seeing around Washington.
This is a security failure, etc., but they're rounded up very quickly by the FBI working from social-media and news footage. They go to jail.
It's a very short film.
The 1984 Red Dawn's actually okay. There are whole stretches (from memory) in which it's possible to suspend disbelief.
Capitol? Nah, ridiculous. In the real world they'd have a plan, at least. Wouldn't they?