Tens of thousands of South Koreans rallied Saturday night against a government decision to import U.S. beef in the largest demonstration in a month of almost daily protests. ADVERTISEMENT A crowd estimated by police at 38,000 people filled a plaza in front of city hall. Protesters lit candles, waved placards and chanted slogans criticizing President Lee Myung-bak. South Korea agreed in April to reopen what was formerly the third-largest overseas market for U.S. beef. It had been shut for most of the past 4 1/2 years following the first U.S. case of mad cow disease in a Canadian-born cow in...