A plague on both your houses, New York City Mayor Michael Bloomberg says. “Democrats now, and Republicans then, spent more time and energy conducting partisan warfare than forging centrist solutions to our toughest economic problems,” he said in a wide-ranging speech on the Brooklyn waterfront Wednesday. The speech added fuel to continuing speculation that Bloomberg is preparing a third-party run for president, something he has consistently denied. He called for simplified regulations on business, including Wall Street, investment in employment centers, immigration reform and promotion of foreign trade, especially with emerging economies. Bloomberg also came to the defense, as he has before, of big business. “When did success become a bad word in America?” he said.