Election Day exit polls this week made clear that President-elect Barack Obama has a broad mandate to get the faltering U.S. economy back on track. There is no shortage of proposals already circulating in Washington. But as more reports pour in showing the downturn accelerating — and spreading around the world — the short-term impact of the new administration’s policies may be limited. Voters made clear they want the new Congress and Obama administration to make the economy a top priority. More than six in 10 voters surveyed chose the economy as the most pressing issue facing the nation, and...