Federal, State and Local.
People in ANY uniformed service are vetted, trained, taught and REQUIRED to follow orders, no matter what. The officers and state have your job, your salary, your pension and the overall message is that you had better NOT make waves. When confronted with an illegal order there is no support for refusing it.
This is why we have SWAT team raids for misdemeanors, Waco, Ruby Ridge, New Orleans and any number of atrocities performed by people who have sworn an oath to protect and defend, uphold the constitution and the BOR.
If the sworn uniforms in N.O. had been ordered to line people up and shoot them, the only question would be: do you want them shot in the front or the back? Units might have been uneasy. Some commander might have his folks control traffic and load magazines instead of actually shooting, but no one would have protested loudly, refused, or RESISTED others who followed plainly illegal orders. They got people to gas and drive tanks into a building full of women and kids, then burn it down, let it burn, then bulldozed and hid the evidence and let the bodies rot in a trailer in Ft Worth. Then put the cover up in place. I have a friend who testified he watched them load the missing Waco front door on a truck. He's disgusted...but he STILL WORKS WITH THE FEDS.
No one refuses. Ever.
IMHO, of course. Some may think that instead they would protect and serve, or uphold the BOR.