The crippled law firm Dewey & Leboeuf filed for chapter 11 bankruptcy protection on Monday night and will seek approval to liquidate its business after failing to find a merger partner, marking the biggest collapse of a law firm in US history. "During the first quarter of 2012, the firm was confronted with liquidity constraints that led to the precipitous resignation of over 160 of the firm's 300 partners by May 11," the New-York based firm said. Dewey listed liabilities in the range of $100m to $500m, according to the filing. It had already terminated 433 of its 533 New...