With the midterms only four weeks away, political polling is near the top of the news. Over the weekend, The Economist reported that “Democrats are heavy favorites to flip the House.” That’s not surprising. In four of the last five midterms, the president’s party lost control of the House. The Economist also predicted “Democrats have a three in five chance of taking the Senate,” an outcome that is relatively rare. The president’s party lost control of the Senate in only two of the last five midterms in 2006 and 2014.