President Donald Trump’s decision Monday to end six-month waivers from U.S. sanctions for five countries that have continued buying Iranian oil — the latest turn of the screw in his Administration’s “maximum pressure” campaign against Iran — was met with predictable outrage from Tehran. But some U.S. State Department, Defense and intelligence officials and outside experts warn that the move could backfire by causing ripple effects in countries like China, Turkey and Iraq. In response to the sanctions, Greece, Italy and, Taiwan had stopped buying Iranian oil, but China, India, Japan, South Korea, and Turkey have continued to import Iranian oil.