"There is an uneasiness among the boots on the ground. Everything we do now can be called into question."

There is no tying the tension here to any specific confrontation gone bad. No shooting, no beating captured on video. Rather, it is akin, law enforcement officials and community leaders said, to a powerful aftershock that has reignited long-unresolved social grievances in Providence and in many other cities across the country following the wave of civil unrest that swept through Ferguson, Albuquerque, Baltimore, Chicago, Cleveland, North Charleston, S.C., and Staten Island.

In the past 16 months, the so-called “Ferguson Effect” has become a staple in the American vernacular. Yet very few agree on what exactly that means and what it may portend for the future relationship between law enforcement and the communities they serve.

In Chicago, now roiled by the police shooting of a black teenager, Mayor Rahm Emanuel suggested earlier this year that the national backlash against allegations of police brutality following Ferguson had caused police to disengage, resulting in recent spikes in violent crime. FBI Director James Comey drew the ire of the White House in October when, like Emanuel, he proposed that recent surges in violence may be explained by “a chill wind that has blown through law enforcement.’’ Milwaukee Police Chief Ed Flynn, meanwhile, recently lamented that local law enforcement had all but been abandoned by the federal government, which has mounted more than 20 investigations of local police operations since 2009, with the most critical examination prompted by the shooting of black teenager by a white police officer in Ferguson.

If there is a common thread, it is a theme of law enforcement under siege where the smoke and embers of more than a year of civil unrest has ushered in an era of persistent suspicion.