Actually,, to follow up from what Terrance said, The major culprits were the ratings /insurance agencies rating the mortgage loans. Not Obama trying to loosed mortgage guidelines. I have been in the mortgage biz since '92, and knew guys employed by the rating agencies. The took B & C paper and rated it AA or AAA due to pressure from the big banks. This came about because first Clinton(with the repub congress pushing him) weakened the bank regulations controlling the derivatives. Then when W got in power, he removed the remaining wall requiring a modicum of accountability for the banks and Wall Street. The banks could not have offered those loans without colluding with the ratings agencies(think AAG) and Wall Street(who was making a huge profit at the point of sale of the loans). They all enabled each other because it was easy money. The Great Recession was caused by lax regulation of banks and Wall street. It is a historical cycle. The upper class(Wall Street, Big banks, the financial sector, take your pick) periodically take capitalism over the edge and threaten to crash the experiment. And then the rest of us obligingly bail them out, as we did in 2008-2009. Conservatives consistently want to loosed regs, and liberals want to tighten them to prevent the calamity from happening again.