"It's a funny sort of war that produces a lower body count than there was before the war began," writes Jesse Walker for Reason's Hit & Run blog.
As you can see by this graph shows the per-capita number of cops who died of non-accidental gunshots over time (as measured by the Officer Down Memorial Page) has been on the decline since prohibition ended, and 2015 cop deaths will probably be lower than every year since 1870, except for 2013.
Nick Gillespie has more about the mythical "War on Cops" on The Daily Beast:
First—and most importantly—there is no “war on cops,” if the term suggests increasingly brazen and numerous open “executions” of police officers. The National Law Enforcement Officers Fund, which tracks police deaths, finds that the number of police killed in assaults so far this year is 25, the same as last year. The FBI says that while the number of cops “feloniously killed” each year has fluctuated over the past decade, “it stands at about 50.” As my Reason colleague Ed Krayewski writes, “In 2007, there were 67 cops shot and killed in the line of duty. In 2007 there was no ‘national conversation’ about police reform, no sustained focus on criminal justice reform, nothing in the national zeitgeist that would suggest the number of murders were the result of anything more than the number of people who had killed cops that year.”
Second, to the extent that there is serious discussion about reforming criminal justice practices, it is driven by highly publicized cases of overreaction or brutality by law enforcement that is increasingly visible due to smart phone cameras and social media. The 2011 case of Kelly Thomas, a 37-year-old schizophrenic drifter beaten to death by Fullerton, California, police, perfectly illustrates the real “new world” faced by police. It was only after Thomas’s father took gruesome pictures of his comatose son’s severely battered body and face and shared them via social media that public pressure grew for a full investigation and trial.