The drop in oil prices was supposed to help the economy this year. So far, it seems to have mostly hurt. The theory of why lower oil costs should boost U.S. growth is simple. Despite gains in domestic production from the shale boom, the country is a still a net importer of crude. So when oil prices fall, American consumers and businesses spend less money on stuff produced abroad, leaving them with more to spend on stuff produced at home. And gross domestic product goes up. Yet GDP expanded at an annual rate of just 0.2% in the first quarter-a figure likely to be revised lower. And while some weakness was due to severe weather and West Coast port problems, growth this quarter is looking muted. Forecasting firm Macroeconomic Advisers expects GDP to grow […]