The billboard is the work of a group called the Courage Campaign, whose president says it's time to get the country behind the removal of Mr. Trump. They want to pressure the Republican-controlled Congress, which has shown no inclination to impeach the president.
"We are a grassroots organization. If we are not calling for impeachment, given what has happened, who is?" asked the organization's president and executive director, Eddie Kurtz. He points out that more than a million people cross the bridge every day, so it's an incredibly strategic place to have a billboard.