An excerpt from Johnson's column:
"The FCIC Republicans point the finger firmly at Fannie Mae, Freddie Mac, and other government-sponsored enterprises that supported housing loans by providing guarantees of various kinds. They are right that Fannie and Freddie were 'too big to fail,' which enabled them to borrow more cheaply and take on more risk—with too little equity funding to back up their exposure.
"But, while Fannie and Freddie jumped into dubious mortgages (particularly those known as Alt-A) and did some work with subprime lenders, this was relatively small stuff and late in the cycle (e.g., 2004-2005). The main impetus for the boom came from the entire machinery of "private label" securitization, which was just that: private. In fact, as Acemoglu points out, the powerful private-sector players consistently tried to marginalize Fannie and Freddie and exclude them from rapidly expanding market segments.
The FCIC Republicans are right to place the government at the center of what went wrong. But this was not a case of overregulating and overreaching. On the contrary, 30 years of financial deregulation, made possible by capturing the hearts and minds of regulators, and of politicians on both sides of the aisle, gave a narrow private-sector elite—mostly on Wall Street—almost all the upside of the housing boom.
"The downside was shoved onto the rest of society, particularly the relatively uneducated and underpaid, who now have lost their houses, their jobs, their hopes for their children, or all of the above. These people did not cause the crisis. But they are paying for it."
Of course, there was no single cause of the crisis...it was the result of a confluence of factors. What's more, it will do us little good to discover the cause of the last crisis, because there will inevitably be another crisis down the line with totally new and different causes. Still, it is human nature to try. The government recently put out its 662-page Financial Crisis Inquiry report on the causes of the crisis.