Trump won't use tariffs "like a madman" - WaPostAs for Mr. Trump’s many hard-line positions, he implied on Sunday that some of them might be opening moves in longer negotiations. Even as he pledged to raise tariffs and admitted that such a move could push up prices, he said he would not “use them like a madman" and noted Americans’ discontent over grocery costs. His threat to slap 25 percent tariffs on Canada and Mexico could certainly qualify as a “madman” move, considering the harm it would do to raise prices on goods from trading partners so deeply integrated with the U.S. economy.