President Barack Obama warned Wall Street this afternoon against returning to the reckless behavior that threatened the nation with a second Great Depression. Even as he noted the U.S. economy and financial system were pulling out of a downward spiral, he warned financial titans that they could not count on any more bailouts. In marking his determination to prevent a repeat of the crisis that nearly brought down the global financial system last fall, Obama said he was attacking the problem on several broad fronts, including asking Congress to approve new rules to protect consumers.