The coming shift is due, at least in part, to a structural change. The voter-approved decision to switch from citywide to district-based elections in 2015 made greater turnover possible. When council members were elected citywide, the number of positions up for re-election alternated every other year from five to four. In 2015, however, all nine seats were contested as the city settled into its new system. Now, elections alternate between electing the seven district seats and the two citywide seats. The result is a potential for more turbulence, with large turnover more likely every four years.

Past periods of rapid turnover have tended to correspond to particular movements or scandals.

In the years from the late 1960s to the early 1970s, the entire city council turned over. Some of this was the result of tragedy: Wing Luke died in a plane crash near Stevens Pass in 1965. But much of it was thanks to a movement that called itself Choose an Effective City Council (CHECC). The organization emerged during a period of broad upheaval across the country. It was a challenge to the perceived entrenched powers on the city council and — in contrast to some of the activist movements of today — cast itself as collaborative and bipartisan. For example, before the CHECC era, council members Mike Mitchell and Clarence Massart had sat on the council for decades. The period that saw the elections of Sam Smith, Phyllis Lamphere and others changed all that.

Another notable time of turnover came in the early 2000s, following the “Strippergate” scandal — or, as the New York Times called it at the time, “A Tale of Sex, Money and Politics, in ‘Mayberry.’” The scandal was rooted in the deeds of crime boss Frank Colacurcio Jr., who made donations to three council members just as the council was considering whether to allow him to expand a parking lot near his strip club, Rick’s.