Sometimes I hear white anti-racists say they think that police are on the front lines of maintaining white supremacist culture. But I think that's a type of cop out. (Pun intended)
White culture built on white history is on the front lines of maintaining white supremacist culture. Cops are simply the most visible part of it.
Imagine America being made up of 1000s and 1000s of cheerleader pyramids. Imagine that these human pyramids are built just like they are in real life, everybody starting off on the ground climbing on top of others, working cooperatively to build a solid structure in the same way you build many elements of a society.

The people at the base of each pyramid represent the general population. People in the middle can fill all sorts of middle management life slots.But in this case, let's imagine that a cop is that individual that made it to the top of each cheerleader pyramid.
The thing to keep in mind is that the person who decided to be a police officer started on the ground just like the rest of the cheerleaders. So if the cops at the top is a white supremacist that's because he came from a field of white supremacists. He or she wasn't plucked from another planet and placed on top by God.
In other words, police officers are a product of their culture. They are born. They are created. They follow. They don't lead.
If a black woman like myself was drawing similar human pyramids to describe white supremacy in 1715, it's likely she could tell you more precisely which section of the white population each layer of people represents more precisely.
- The bottom layer would be the poor white farmers, who own no slaves, the ones who wonders if they will eat grass when the crops don't come in. This is the white person whose only item of value is his white skin. And feeling superior to blacks they will report runaway slaves as quickly as possible for the personal satisfaction when he can only hope for a reward.
-The next layer up in 1715 might be the overseers, who don't own slaves either. This layer might also contain neighbors that rent or borrow slaves as well as bankers that take slaves as collateral.
- By the 1830s the layer after that would have a sizable percentage of northern white abolitionists who abhor the stories of beatings, rape, and torture associated with slavery but have never one thought of black people as being their equals. These are the white supremacists who favor peacefully getting along until blacks can be sent back to Africa.
-The slave owners would be the ones held in place at the top of pyramid.
The point is that not everyone owns slaves in the 1715 human, white supremacy, pyramids. Yet nearly every white someone is a part of the structure and benefits in some way. Even the poorest white person can repeat to himself what the rich white man has told him, "I may be dirt poor, but at least I'm not black."
All components are part of holding the slave owners steady at the top.
Three hundred years later, in 2015, the white supremacy structure is constructed in the same way. Cops are at the top of many pyramids, but they aren't lonely up there. White supremacy embracing judges, elected officials, bankers, and corporation giants are also being held steady at the top
--and there's the occasional Dylann Foot that slips out from the bottom and scrambles high enough that he too can lash out -- just like some of the cops.
Again, white culture is the leading edge of white supremacy with police forces across the U.S. being the most visible.
And police officers are visible because they are the ones that are hands-on, the ones in charge of making sure black people remember their place, using violence so erratically that everyone with dark skin is terrorized whether they've been personally abused or not.
By the way...
It's no accident that I chose these particular cheerleader pyramids to represent the thousands of cheerleader pyramids of my metaphorical America.
There are black or brown people in each pyramid because the Ben Carsons and Clarence Thomases as well as black and brown cops have to do their part in order for white supremacy to remain solid and intact.
The Bens and Clarences are necessary as they decrease the chances of white supremacy recognizing itself in the mirror.
Example 1: Old Style Lynching
If every single black agrees that thing X is racist, there's no room for white denial to exist in regards to thing X.