Barack Obama clearly has the financial advantage over John McCain when it comes to hard campaign funds. But in the less transparent world of independent groups, conservative organizations have been spending about 75 percent more money on TV time for anti-Obama attack ads than liberal groups have spent to defeat McCain.

According to our analysis of the latest numbers from the Campaign Media Analysis Group, conservative groups like Vets for Freedom and American Issues Project have spent about $9,427,000 on TV airtime, while liberal groups like labor unions and spent $5,351,000 since the beginning of July. That’s chump change compared to the candidates’ ad buys, but sometimes an outside attack can do what the candidate can’t, or won’t. For instance, we count four different groups that have run ads linking Obama to former radical Bill Ayers, even when the McCain campaign itself wasn’t making that argument.

To be sure, this isn’t the full picture. Advocacy groups are spending many millions more on radio ads, direct mail, phone calls and canvassing — and none of that shows up in these numbers. Plus, a group like Brave New PAC spent very little on TV time, but generated a lot of attention for its online anti-McCain videos. One other caveat: CMAG numbers are just estimates, and the ad-tracking service doesn’t pick up the National Rifle Association’s ads, and others, on local cable stations.

To make the calculation, we excluded ad buys that clearly meant to advance a partisan agenda but didn’t refer to a presidential candidate, like those from the liberal Health Care for America Now and the conservative Employee Freedom Action Committee. We even took out an American Issues Project ad attacking Senate Democrats because it didn’t mention Obama. If you add those in, conservatives have outspent liberals nearly two to one since July. Why July? That’s the first month after the primaries ended.

Here’s the breakdown.

Liberal Groups

Service Employees International Union = $1,999,602
United Auto Workers = $1,104,206 = $1,008,080
Planned Parenthood = $330,066
VoteVets = $196,320
Defenders of Wildlife = $156,575
Bring Ohio Back = $127,436
AFL-CIO = $123,274
AFSCME = $82,263
PowerPac = $79,880
United Food & Commercial Workers = $70,841
California Nurses Association = $60,316
Matthew 25 Network = $8,858
Brave New PAC = $3,293

TOTAL = $5,351,010

Conservative Groups

Vets for Freedom = $3,906,472
American Issues Project = $1,867,872 = $1,475,581
Committee for Truth in Politics = $1,056,309
Let Freedom Ring = $652,424
Judicial Confirmation Network = $194,283
Born Alive Truth = $165,948
Citizens United = $54,439
Our Country Deserves Better = $28,711
National Republican Trust = $25,162

TOTAL = $9,427,201

There’s less than two weeks to go. The liberals could pull ahead — or the conservatives could pull away. All coming to a TV screen near you.

This originally appeared on The Secret Money Project Blog, a joint project of CIR and National Public Radio tracking the hidden cash in the 2008 election.

Creative Commons License

Republish our articles for free, online or in print, under a Creative Commons license.

Will Evans is a senior reporter and producer for Reveal, covering labor and tech. His reporting has prompted government investigations, legislation, reforms and prosecutions. A series on working conditions at Amazon warehouses was a finalist for a Pulitzer Prize and won a Gerald Loeb Award. His work has also won multiple Investigative Reporters and Editors Awards, including for a series on safety problems at Tesla. Other investigations have exposed secret spying at Uber, illegal discrimination in the temp industry and rampant fraud in California's drug rehab system for the poor. Prior to joining The Center for Investigative Reporting in 2005, Evans was a reporter at The Sacramento Bee. He is based in Reveal's Emeryville, California, office.