It seems obvious to me that as we work toward decarceration and decriminalization there will be a need for fewer police officers.
Practically everyone agrees that racial profiling should go away. Well, that's less "work" and should lead to fewer staff. Pretty similar public sentiment toward drug possession.
Not quite cops, but related. If we got rid of cash bail we'd need smaller prisons and fewer corrections officers. People who are released without bail overwhelmingly return for their court dates. So the only reason they are in jail is because they couldn't afford bail--they haven't been convicted of a crime. And that bail is then used to coerce confessions out of people.
On a given night, about 470k people are in jail because they couldn't make bail. That's about 25% of incarcerated people.