How many police do yo think are in the entire USA? The next question would be how many police/soldiers does it take to subdue 300 million?
More than half of that 300 million will be non-combatants. Nearly half of those remaining will be on the side of the regime, ready to rat out suspected Patriots. Of those left, how many will actually take up arms, or sabotage regime forces, poison their food and water, or set the IEDs...in short, go guerrilla?
That's why it is important to take out leadership early on.