So we do not forget why we have this economic crisis

Bloomberg explains it all so well:

http://www.bloomberg.com/apps/news?pid=20601039&refer=columnist_wallison&sid=a6M1QA55PB9Y

Some excerpts:
"There has been a great deal of deregulation in our economy over the last 30 years, but none of it has been in the financial sector or has had anything to do with the current crisis. Almost all financial legislation, such as the Federal Deposit Insurance Corp. Improvement Act of 1991, adopted after the savings and loan collapse in the late 1980s, significantly tightened the regulation of banks."

"Republicans have favored financial regulation where it was necessary, as in the case of Fannie Mae and Freddie Mac, while the Democrats have opposed it. In 2005, the Senate Banking Committee, then under Republican control, adopted a tough regulatory bill for Fannie and Freddie over the unanimous opposition of committee Democrats. The opposition of the Democrats when the bill reached the full Senate made its enactment impossible.
Barack Obama did nothing; John McCain endorsed the bill in a speech on the Senate floor. "