In Donald Trump’s first term in office, the American Civil Liberties Union filed four hundred and thirty-four lawsuits against the Administration. Since Trump’s second Inauguration, the A.C.L.U. has filed cases to block executive orders ending birthright citizenship, defunding gender-affirming health care, and more. If the Administration defies a judge’s order to fully reinstate government funds frozen by executive order, Anthony Romero, the A.C.L.U.’s executive director, says, we will have arrived at a constitutional crisis. “We’re at the Rubicon,” Romero says. “Whether we’ve crossed it remains to be seen.” Romero has held the job since 2001—he started just days before September 11, 2001—and has done the job under four Presidents. He tells David Remnick that it’s nothing new for Presidents to chafe at judicial obstacles to implement their agendas; Romero mentions Bill Clinton’s attempts to strip courts of certain powers as notably aggressive. But, “if Trump decides to flagrantly defy a judicial order, then I think . . .  we’ve got to take to the streets in a different way. We’ve got to shut down this country.”