There is a viral blurb about how McCain supported reform of Fannie and Freddie Mae. It talks about how Senate Democrats killed the Federal Housing Enterprise Regulatory Reform Act of 2005, S. 190 which was co-sponosored by McCain.
McCain made a reformer's speech. You can find it here:
http://www.govtrack.us/congress/record.xpd?id=109-s20060525-16&bill=s109-190You can google this bill and find references to McCain's pro-reform role proliferating throughout the net.
The answer is that both Democrats and Republicans wanted to pass new regulations on Fannie and Freddie (GSEs), but that the Republicans in the Senate (McCain) wanted to remove pro-affordable housing elements of the House bill and presumably they eventually wanted to let the "generous" private sector lenders (like Countrywide) take over new loans. The Democrats wanted tighter regulations and affordable housing. So Republican's were happy to regulate the GSE based loan companies and at the same time limit affordable housing. Dems wanted both affordable housing and tighter regulations.
One can ask where were the proposed regulations for the private sector?
Here is an article about the legislation at the time:
http://goliath.ecnext.com/coms2/summary_0199-4747361_ITM