Can’t you be both pro-police and anti-excessive force?

That very reasonable but fine line has begun to feel like a tightrope in the days since the execution-style murder of two New York City police officers on Dec. 20. The absolutist rhetoric being hurled on both sides of the divide is unhelpful and disappointing, especially when it is advanced by people who should know better.

Moderate voices need to step up to the extremists on both sides – from those who would cast all police as racists to police union officials who read any critique as an abject betrayal. They’re both wrong.

Responsible citizens – especially people in communities like our own – understand that law enforcement personnel have a very difficult, stressful and sometimes hazardous job. Police officers and their families in this community are held in very high regard – and they’ve earned that distinction through their service and sacrifice. They are our neighbors, friends, spouses, children, and family members.

But that does not mean that individual instances of police misconduct should reflexively be defended or shrugged off as the occasional cost of doing business. In those instances in which police officers have injured or killed civilians, the public has every right to expect that justice will be served. And, when justice proves elusive, the American people have an obligation to demand a change in course.

The protests that have manifested themselves across the country have been rooted in that conviction. The failure of local authorities to indict police officers in civilian killings has become a systemic problem – and one that threatens to undermine faith in our system of justice and the rule of law.

As in all mass protest movements, the motives and tactics of the protesters can be confusing and, sometimes, fringe elements can render otherwise purposeful protests into something other than that. Officers, some of whom have been subjected to insults that are not warranted, are right to feel frustrated when their personal reputation is called into question. Here in Boston, these officers and their commanders have shown the professionalism that we have come to expect from them in managing public protests. And we expect that will continue.

The deaths of two NYPD officers at the hands of a man who had already attempted to kill his ex-girlfriend earlier that day shook that city and the country – as it should have. But those who immediately linked the atrocity to earlier statements of support for reform were irresponsible and divisive. Subsequent actions – including by some police who turned their backs on New York City Mayor Bill de Blasio at a funeral service for one of the two slain officers this week – were poorly-timed and unprofessional. We should expect more from our public servants.

Finding common ground in this tense moment will require responsible leadership from moderate voices on both sides of the debate. In New York, de Blasio has shown admirable restraint by not escalating the war of words initiated by reckless political foes, including one of his own predecessors. Here in Boston, our own leadership – Mayor Martin Walsh, Commissioner Bill Evans and elected officials of color and religious leaders – have set the right tone in their comments and actions.

The nation wants and deserves such moderation from its leaders, but that stance cannot be a stand-in for justice. Decisive action is required at the federal level to ensure that civilian killings by police are urgently pursued by the Department of Justice in instances when local jurisdictions fail to proceed with criminal charges. Until then, there will remain a reasonable doubt about whether all lives are truly considered equal under the law. That doubt is a reality that cannot stand, especially within communities of color. It is also an unfair burden to put on the good men and women of law enforcement who conduct themselves with restraint and – in the absence of justice – are sullied by the actions of a few.

In this instance, no one should feel compelled to pick a side.