Despite their funding deluge from wealthy donors, Republicans failed to overwhelm President Barack Obama and Democrats at the ballot box. So was throwing all that money at the 2012 election worth it?

Obama was handily re-elected, Democrats added two more seats to their majority in the Senate, and they cut into the Republican lead in the House.

There is no two ways about it: that spelled bad news for Karl Rove, president George W. Bush's then-strategist and a party luminary who raised huge money for Republican efforts across the United States this year.

His two groups, super political action committee (PAC) American Crossroads and its general interest group cousin Crossroads GPS, funneled at least $176 million of donor money into anti-Obama advertising and Republican candidates, who lost en masse on November 6.

Some reports put the dollar figure above $300 million.

In its historic 2010 ruling, "Citizens United vs Federal Election Commission," the US Supreme Court struck down limits on corporate campaign spending, essentially giving companies the same basic right to political speech that individuals have.

By contrast, donations to the candidates and political parties themselves remained capped.

Citizens United unleashed a torrent of funds from corporations and wealthy individuals -- on both sides of the political fence.

The Sunlight Foundation, which advocates greater transparency in government and elections, estimated that outside groups spent a total of more than $1.3 billion in independent expenditures to influence the outcome of the 2012 races.

In the case of a public policy advocacy group like Crossroads GPS, spending must be reported but the donor information can be kept confidential, allowing billionaire conservatives to spend sky-high sums without being identified.

Casino magnate Sheldon Adelson acknowledged parting with no less than $54 million of his own money to try to get Romney elected.

But of the 14 races targeted by American Crossroads, just three were won by Republicans, according to an analysis by the Center for Responsive Politics, a group that publishes election expenses. Crossroads GPS fared only slightly better; the group was seven for 24 in its races.

Factors well beyond money helped explain the outcomes in multiple races, but progressive groups had feared that wealthy conservatives' blank checks would swamp less heavily invested liberal candidates running in smaller, out-of-the-way areas.

"The candidates sometimes don't have enough resources of their own to make themselves well known to the electorate," Bob Biersack, senior fellow at the Center for Responsive Politics, told AFP.

"People don't know them to begin with, so you can shape people's judgment about candidates more easily in those kind of districts" with big money invested by super PACs.

Crossroads sees the glass half full. According to its communications director Jonathan Collegio, the group helped offset the fundraising juggernaut that was the Obama campaign, which spent $541 million compared to the Romney campaign's $336 million.

"Crossroads played a critical role of balancing out those efforts, and had we not been there, it's safe to say that the outcome would have been considerably worse," Collegio said.

The strategist is confident about his group's role in the future, and said he did not fear a decline in contributions from wealthy donors.

Former investment fund manager Foster Friess, who spent $5 million on Republican races this year, told the Los Angeles Times that contributions to such independent groups "will not drop off" in the 2014 mid-term election and then the 2016 general.

Crossroads won't be waiting until then. It confirmed to AFP it will air advertisements aimed at influencing upcoming negotiations on the US budget and encouraging policies that decrease taxes for US companies and budgets.