Democratic leaders aren’t calling for the impeachment of President Donald Trump. But they’re getting closer. To one Democratic congressman, the president’s decision to fire FBI Director James Comey reminded him of the “doomsday clock,” a symbol that warns about the likelihood of nuclear war. “We should maybe have an impeachment clock,” Rep. Mark Pocan, D-Wis., said on Wednesday. “And if we did, I think yesterday moved us about an hour closer to having that need.” Pocan said he had thought Democrats in the House of Representatives needed to use the threat of impeachment as a “tool” to make the administration...