THE VIDEO of Brad Lander getting slammed against a wall and arrested by federal immigration agents shocked New Yorkers, who are not easily shocked. On June 17th the mild-mannered city comptroller had been attempting to escort a migrant through a federal building in Manhattan as agents tried to detain the man. “It’s bullshit,” said Kathy Hochul, the Democratic governor of New York, of Mr Lander’s arrest. It came a week before a crowded Democratic primary for New York City mayor, in which the city comptroller is a candidate. The arrest may well help his campaign, but it marked yet another skirmish over immigration with Donald Trump’s administration. It is just the latest escalation in a confrontation with cities and states that did not vote for the president, on a topic where the public supports him most.