Do some research.
Start with Freddie Mac and Fannie Mae. Look up names, past and present connections, and who did what, when. Do a bit of research on who proposed tightening their regulation environment, and who fought it. Look up who were the recipients of their campaign contributions, and the lobbying activity. You can move beyond it to look at the regulation history in other mortgage areas, including the basic concept of taxpayer-backed mortgages in the first place.
So, who's left to vote for? The belief that the issues you raise are "Republican" is infantile.