An economist said that undermining the independence of the Fed could shrink the American economy and cause capital to flow to other countries.Drew Angerer/Getty ImagesEconomists at the Peterson Institute studied what would happen if Trump undermined Fed independence.They found that GDP would shrink, inflation would rise, and capital would flow to other countries.One of the researchers spoke to BI about the findings and said that recovery could take decades.In August, Trump floated the idea that, as a successful businessman, he should have "at least" a say in the Federal Reserve's monetary policy.A new study by the Peterson Institute of International Economics, a renowned nonpartisan think tank, found that such an idea could have catastrophic economic consequences.