Much of the tens of millions of dollars raised as a result of the ruling has been "dark" -- donors not identified.
But the impression that Republicans benefited more from the outside expenditures than Democrats turned out not to be true, though the GOP benefited much more from the "dark" portion.
The 5-4 decision along the Supreme Court's ideological divide in Citizens United vs. Federal Election Commission generated more than one of the most expensive midterm elections in the nation's history. It sparked a caustic feud between the White House and several conservative Supreme Court justices, who like to think they are above politics. It gave Republican strategist Karl Rove a new opportunity to re-emerge as the dark prince of the GOP. It gave Republicans realistic hope not only of sweeping future congressional elections, but of taking back the presidency in 2012.
Depending on your point of view, the Citizens United decision either leveled the playing field for political speech -- it erased restrictions that kept corporations and unions from using their own funds to buy "electioneering communications" 30 days before a primary or 60 days before an election -- or it threw away 100 years of law and Supreme Court precedent to give money an even more crucial role in U.S. politics.
Writing for the narrow majority in the prevailing opinion, Justice Anthony Kennedy depicted restrictions on corporations -- restrictions that didn't affect individuals -- as injustice pure and simple.
"The censorship we now confront is vast in its reach," Kennedy said, citing earlier Supreme Court opinions. The government has "'muffled the voices that best represent the most significant segments of the economy' ... and 'the electorate (has been) deprived of information, knowledge and opinion vital to its function.' ... By suppressing the speech of manifold corporations, both for-profit and non-profit, the government prevents their voices and viewpoints from reaching the public and advising voters on which persons or entities are hostile to their interests. Factions will necessarily form in our republic, but" -- citing the Federalist Papers -- "the remedy of 'destroying the liberty' of some factions is 'worse than the disease.' ... Factions should be checked by permitting them all to speak ... and by entrusting the people to judge what is true and what is false."
Retiring Justice John Paul Stevens, the leader of the dissenters, had a harsh though somewhat sad rejoinder.
"The court's ruling threatens to undermine the integrity of elected institutions across the nation," he said. "The path it has taken to reach its outcome will, I fear, do damage to this institution."
Later, he added, "At bottom, the court's opinion is ... a rejection of the common sense of the American people, who have recognized a need to prevent corporations from undermining self-government since the founding, and who have fought against the distinctive corrupting potential of corporate electioneering since the days of Theodore Roosevelt. It is a strange time to repudiate that common sense. While American democracy is imperfect, few outside the majority of this court would have thought its flaws included a dearth of corporate money in politics."
If the majority thought that would be the end of the criticism, President Barack Obama destroyed that notion days later in his State of the Union address.
"With all due deference to separation of powers," Obama said in his nationally televised speech, "last week the Supreme Court reversed a century of law that I believe will open the floodgates for special interests, including foreign corporations, to spend without limit in our elections." The president spoke as conservative members of the Supreme Court sat and steamed below him in the chamber.
Justice Samuel Alito was visibly angered, at least twice mouthing, "Not true" as the president spoke. Chief Justice John Roberts was so upset at the unprecedented direct criticism he later suggested there was no need for justices to attend future State of the Union addresses.
Also during the State of the Union address, Obama spoke hopefully of Congress acting quickly on legislation to repair the political system and undo the ruling. That hope appears to have evaporated with the new political reality.
Rhetoric aside, how much and what kind of outside contributions did the Supreme Court ruling generate?
The non-profit educational organization, the Sunlight Foundation, said in a posting Nov. 4 outside-party groups raised and spent $126 million on the elections without disclosing the sources of the money.
That $126 million from undisclosed sources added up to more than a quarter of the $450 million spent by outside groups on the midterms. Some $60 million more was spent by groups who were allowed to raise money without limits but still had to disclose the sources.
The total amount of outside money made possible by the Citizens United ruling reached $186 million, or 40 percent, of the total spent by outside groups, the foundation said.
The money tended to flow toward Republicans. GOP groups raising unlimited money, while disclosing the money's sources, spent $35.7 million -- $11 million more than similar Democratic groups. But when looking at groups that failed to disclose their donors, Republicans outspent Democrats six to one, the foundation said -- $59 million to $10 million.
Crossroads GPS, a group linked to Rove which does not disclose its donors, spent 75 percent of its money in races where the Republican candidate won, the foundation said. The group spent $4.4 million -- the most it spent in any race -- opposing Democratic candidate Alexi Giannoulias, who lost a close U.S. Senate race for Obama's old seat to Republican Mark Kirk by 2 percentage points.
Other Republican groups, including another Rove-linked organization, American Crossroads, spent most of their money in races won by Republicans, the foundation said.
The foundation posting said Democratic-linked groups, including big unions, didn't do as well in the election. The union for public sector workers, the American Federation of State, County and Municipal Employees, spent $6.51 million -- 85 percent of its money -- in races Democrats lost.
So what's the bottom line?
Mother Jones, the left-wing investigative magazine, said there was little evidence outside money benefited Republicans more than Democrats.
Outside groups backing Republicans spent $197.4 million; outside groups backing Democrats spent $181.1 million, the magazine said. Most of the outside money on each side was spent on negative attack ads -- $155.9 million on ads attacking Democrats, $144.8 million on ads attacking Republicans.
Mother Jones said Democratic support with disclosed donors was likely to come through party committees like the Democratic Senatorial Campaign Committee, while Republican support was more likely to come through "darker" outside groups like American Crossroads or Crossroads GPS, which spent $21.5 million and $16.7 million, respectively.
Meanwhile, The New York Times says the trend of using outside groups and anonymous donations is just beginning and plays a large part in Republican planning to take back the White House in 2012.
In an article published in the Times Oct. 31, officials with American Crossroads and Crossroads GPS said they would continue anti-Democratic advertising as Congress returns and takes on the issue of extending the Bush-era tax cuts.
Robert M. Duncan, chairman of American Crossroads, told the Times he also informed major donors in October that "research and development" would make the groups more effective in the next election.
"It's a bigger prize in 2012, and that's changing the White House," Duncan told the newspaper. "We've planted the flag for permanence, and we believe that we will play a major role for 2012."
The Times said Duncan's comments confirmed what Democrats say they fear -- that the major Republican independent groups viewed the 2010 elections as a proving ground for 2012.
Non-party outside group fundraising is not a Republican invention. Democrats set up a network to collect and spend millions in donations from unions, corporations and the wealthy in the 2004 presidential campaign of U.S. Sen. John Kerry, countering the better-financed campaign of President George W. Bush. But the Democratic money groups were set up as political committees, the Times said, and had to report the identities of their donors for tax purposes.
Obama's campaign in 2008 didn't use the network -- causing it to wither and lose its effectiveness for 2010 -- and instead used money raised from small donations by individual supporters. Democrats now are taking another look at the wisdom of that policy, whatever its morality.