The New York Times Dealbook has an interesting article on why the SEC hasn't sued any Lehman Brothers executives in connection with the 2008 collapse of that firm. The short answer: because they didn't think they could prove those executives violated federal securities law.

The Times article is a strong reminder that business responsibility for a business's collapse is not equivalent to a securities law violation and that the SEC's scarce resources are best directed to violations it can prove. The SEC's role is to enforce the law, not to satisfy the public clamor for a scapegoat.

The Times article is also an interesting story of how an SEC staff member, George S. Canellos, resisted the political pressure to bring a case. Canellos was the head of the SEC's N.Y. office at the time and now heads the SEC's enforcement division. According to the article, he faced strong pressure from then-Chair Mary Schapiro to bring a case, but refused.

The failure to find a case apparently wasn't from lack of trying. According to the Times, the SEC reviewed more than 15 million documents and interviewed three dozen witnesses.