WASHINGTON (AP) — Republican Sen. Bob Corker said Monday he is unsure about running for re-election, injecting fresh doubts into the GOP's efforts to tighten its hold on the Senate majority next year. The Tennessee lawmaker, a sometimes critic of President Donald Trump, expressed his ambivalence in a brief statement, even as he sits on more than $6.5 million in a campaign account. "While we are in a strong position, I am still contemplating the future and will make a decision at the appropriate time," Corker said. He emphasized that "everyone in the Volunteer state knows ...