It's not a theory, it's a fact. The genesis was the Community Reinvestment Act of 1979 under Carter. Clinton accelerated the program and Bush sent out a caveat to get it under control. That fell on the deaf ears of Frank, Dodd, Waters, Meeks, and Franklin Raines. It you can't see the forest for the trees, than watch the video. After that, you might want to change your handle.