Huh? Bush was a huge proponent of subsidizing mortgages, and making it easier for people to get loans without down payments. One of his initiatives: http://www.hud.gov/offices/cpd/affordablehousing/programs/ho...

Barney Frank and a large cohort of liberal representatives fought tooth and nail against Bush's efforts to more strongly regulate Fannie/Freddie, but that's a separate matter. All Bush wanted was more strict regulations of their risks, mainly interest rate risk. All mainstream politicians were (and still are) in favor of inflating the bubble by subsidizing home ownership.