WASHINGTON – President Barack Obama on Saturday unloaded on a divided Supreme Court for allowing more corporate influence over elections. The White House and Democratic lawmakers scrambled to figure out how to blunt the impact of the ruling.

Obama used his radio and Internet address as a platform to expand on criticism Thursday's decision, which drastically alters the rules of campaign finance going into November's congressional elections. The 5-4 decision threw out parts of a law that said companies and unions can be prohibited from using their own money to produce and run campaign ads that promote or target particular candidates by name.

The justices also struck down a measure that had barred union- and corporate-paid issue ads in the pivotal, closing days of election campaigns.

"I can't think of anything more devastating to the public interest," Obama said. "The last thing we need to do is hand more influence to the lobbyists in Washington, or more power to the special interests to tip the outcome of the elections."

Obama promised a forceful and bipartisan response with Congress, but it is unclear how far any legislation can go in trying to undo the court's action.

Negotiations are under way. Norm Eisen, special counsel to Obama for ethics and government reform, met Friday with staff members for Sen. Chuck Schumer, D-N.Y., and Rep. Chris Van Hollen, D-Md., the two lawmakers leading the effort for a legislative response.

Among the ideas under consideration are tougher disclosure requirements for corporations that sponsor ad campaigns; a requirement that any political ads by publicly traded companies be approved by shareholders; and a ban on campaign spending by companies that have received federal bailout money, according to an official familiar with the discussions who spoke on condition of anonymity because no plans have been agreed upon.

Obama is expected to address the broader issue in his State of the Union address on Wednesday.

The court's decision wrestled with the matter of campaign spending as free speech. The majority opinion by Justice Anthony Kennedy made a vigorous argument for the right of the public to be exposed to a multitude of ideas and against the ability of government to limit political speech.

Yet the president is among those who see it as blowing open the doors to big-business influence over democracy. He predicted that anyone who runs for election and tries to take on powerful special interests will now be more likely to be "under assault come election time."

Obama also said the decision will make it harder to enact financial, tax, health care and energy changes.