Congressional Democrats are committing a grave political blunder by continuing to push Russia conspiracy theories and insinuating that Attorney General William Barr is perpetrating a cover-up by complying with the law in his handling of the Mueller report. In addition to the special counsel probe, which produced no evidence of collusion or obstruction of justice by the Trump campaign, there have been two congressional inquiries that also failed to find proof of malfeasance. Several polls conducted since the Mueller probe ended suggest that most Americans believe the President is innocent of wrongdoing and that the Democrats are merely playing politics....