President Donald Trump's top economic adviser, Gary Cohn, said today that he can't guarantee that taxes won't go up for some middle-class families under the administration's sweeping tax overhaul. "There's an exception to every rule," Cohn told ABC News chief anchor George Stephanopoulos in an interview on "Good Morning America." "I can't guarantee anything," said Cohn, the director of the White House Economic Council. "You can always find a unique family somewhere." He said Trump's plan is "purely aimed at middle-class families." But Cohn acknowledged that "it depends which state you live in." "A typical family of four earning $55,000...