Through all the controversy, threats and noise surrounding the Trump-Russia investigation, one person has been conspicuously silent: special counsel Robert Mueller. The former FBI director hasn’t uttered a single word in public since he was appointed in May to lead the probe into Russian meddling in the U.S. election despite increasingly combative attacks by Republicans and their allies on the FBI, the Justice Department and the integrity of his probe. It’s an intentional strategy meant to convey the investigation’s credibility and seriousness in an age of 24-hour noise, amplified by cable news shows and Twitter, according to current and former U.S.