Heinrich Himmler turned the regular police forces into an instruments of terror and used ruthless and cruel methods throughout Germany arresting political opponents and others who refused to obey laws and policies of the Nazi regime.
I'm sure none of the Schutzstaffel woke up one day and decided to execute 15 million people. They were just following orders
Byte has a good thread here about what will "they" say about you when your dead.
When the time comes, I would guess that 75% of the people voluntarily "give up their arms" when the orders come, 23% will hide their guns and hope their never found out (or turn in "some" and hide the rest) and 2 % will be executed in no knock raids as terrorists and said to be a threat to homeland security (or something like that)...maybe it will be that they had received a call of a disturbance and the homeowner opened fire and was killed
Now I'm also not saying that 100% of cops will go out and do the government's dirty work... But most will, many will be neutral and "pretend to play the game" with the department, and a VERY small minority will refuse, and even fewer of those will "take up arms" against the tyranny