President Trump is facing a growing political problem in America’s agricultural heartland, as he looks to import Argentinian beef to help bring down prices for U.S. grocery shoppers. The Trump administration is reportedly looking to quadruple low-tariff imports from Argentina, raising the quota to 80,000 metric tons per year. The news has enraged America’s beef farmers — and the Republican senators who represent them. “This isn’t the way to do it,” Senate Majority Leader John Thune (R-S.D.) said of Trump’s efforts to drive down prices. “It’s created a lot of uncertainty in that market. So I’m hoping that the White...