The subway turnstile — low enough to vault, ubiquitous enough to figure in the lives of millions of New Yorkers each day — has long served as a kind of dragnet for the Police Department. There, officers lie in wait, nabbing those who skip the fare.

Of late, these rotating entry points and those who jump them have become stumbling blocks for Mayor Bill de Blasio, who despite his usual liberal stance on most police issues, has been vocally opposed to the Manhattan district attorney’s office's new policy of declining to prosecute most who are arrested over fare evasion.

De Blasio has adamantly defended the police practice of using evasion of the $2.75 fare as a means for officers to check the names and warrants of those they stop. He has been unpersuaded by critics on the left who believe the approach — pioneered in the 1990s by William J. Bratton, de Blasio’s first police commissioner — is akin to stop-and-frisk, the New York Times reports.