Senator Barack Obama called Thursday for tighter regulation of mortgage lenders, banks and financial houses, even as he spoke of pumping $30 billion into the economy to shield homeowners and local governments from the worst effects of the collapse of the housing bubble.

Mr. Obama laid much of the blame for the crisis on lobbyists and politicians who dismantled the regulatory framework governing the energy, telecommunications and financial services sectors.

Speaking at Cooper Union in Manhattan, Mr. Obama blamed Democrats no less than Republicans for the crisis that now casts a shadow of foreclosure and insolvency over millions of Americans. He did not mention former President Bill Clinton by name, but the target of his criticism seemed clear.

“Under Republican and Democratic administrations, we failed to guard against practices that all too often rewarded financial manipulation instead of productivity and sound business practices,” Mr. Obama said. “The result has been a distorted market that creates bubbles instead of steady sustainable growth, a market that favors Wall Street over Main Street but ends up hurting both.”