Anthony W. Batts, Baltimore’s police chief, was fired in July when rioting broke out after video footage emerged of the police arresting an African-American man who later died in police custody.

Garry F. McCarthy, the police superintendent in Chicago, was abruptly dismissed last week amid civil unrest and rising public discontentment after video footage was released showing an officer shooting an African-American teenager 16 times.

And recent videos of fatal police shootings in San Francisco and Miami Beach have led to calls in those cities for their police chiefs to be ousted.

The tenure of the average urban police chief has never been long or been noted for its serenity, but in an age of widely disseminated video footage of fatal police shootings as well as other accusations of abusive police behavior, some chiefs say a heightened level of scrutiny has radically changed their work — making jobs more difficult, far more political and much less secure. Being fired by a mayor on live television now comes with the territory.