At least since the shooting of Michael Brown in Ferguson, Missouri in August of 2014, every publicized death of an African American at the hands of police has triggered a spasm of protest — before winding down. Though the protests that have erupted across the United States in the three weeks since the horrific killing of George Floyd in Minneapolis on Memorial Day are very different.

For starters, the protests have now been sustained for three weeks with no real end in sight. Second, the numbers — of protesters, protest events, and protest sites — have all grown over time. Though an increase in the number of protesters in the early days of a movement is not unusual, the proliferation of events, and especially protest sites, is rare.

Given the pattern of previous Black Lives Matter demonstrations, the initial wave of protests in major cities around the country was hardly surprising. And the spread of the movement into progressive communities such as Santa Monica, California; Boulder, Colorado; Cambridge, Massachusetts was predictable as well.