What about Home Mortgages don't you understand

1977
President Carter, pressed by grass-roots organizations (though opposed by the banking industry) signed the Community Reinvestment Act to boost lending in poorer communities, regardless of the borrowers' ability to repay their home loans.

1990s
Community organizer Barack Obama worked closely with ACORN activists. Employing the intimidation tactics of radical activist Saul Alinsky that Obama had learned and was teaching, activists crowded bank lobbies, blocked drive-up teller lanes and demonstrated at the homes of bankers to browbeat them into risky lending in poor and minority communities. Those who resisted were accused of racism.
At first, the GSEs resisted purchasing risky mortgages. Eventually the Clinton administration instructed them to substantially increase the percentage of these mortgages in their portfolios.

I thought George W. was the one to blame.

Promote the General Welfare

"So if somebody wants to build a coal-powered plant, they can; it’s just that it will bankrupt them because they’re going to be charged a huge sum for all that greenhouse gas that’s being emitted."

So much for that part of the constitution.