Wall Street greeted a second Obama term the way it greeted the first.Investors dumped stocks Wednesday in the sharpest sell-off of the year. With the election only hours behind them, they focused on big problems ahead in Washington and across the Atlantic Ocean.Frantic selling recalled the days after Obama’s first victory, as the financial crisis raged and stocks spiraled downward. Four years later, American voters returned a divided government to power and left investors fretting about a package of tax increases and government spending cuts that could stall the economic recovery unless Congress acts to stop it by Jan. 1.In Europe, leaders warned that unemployment could remain high for years, and cut their forecasts for economic growth for this year and 2013. The head of the European Central Bank said not even powerhouse Germany is immune.The Dow Jones industrial average plummeted as much as 369 points, or 2.8 percent, in the first two hours of trading. It recovered steadily in the afternoon, but slid into the close and ended down 313, its biggest point drop since this time last year.“It does look ugly,” said Robert Pavlik, chief market strategist at Banyan Partners LLC. He said it was hard to untangle the impact of Europe-related selling from nerves about the nation’s fiscal uncertainty.