The Federal Communications Commission just made the cost of a Senate seat a lot easier to calculate.

Late Friday, the FCC quietly signaled that — opposition from the National Association of Broadcasters notwithstanding — all broadcast TV stations must begin posting political ad buys online as of July 1.

That’s a big deal. It means the FCC faced down a well-funded and influential constituency. And it means voters in six states with heated Senate races, but no top-tier TV market, now will be able to find out just who is paying for all the political ads clogging their airwaves and just how much they are spending.

For the past two years, the FCC has required online posting for only about 200 of the nation’s nearly 2,000 broadcast stations: those affiliated with one of the four top broadcast networks (ABC, CBS, Fox and NBC) and located on one of the 50 biggest TV markets.

That left out a lot of territory — some of it key this year, when the biggest political prize is control of the U.S. Senate. Of 12 races that respected political prognosticator Charlie Cook has identified as this year’s most competitive, seven are in states without a top-50 TV market. You can see the list below.

Sunlight knows from experience just how important and revealing the data contained in political ad files can be. More than two years ago, we began what then seemed to be a zanily ambitious effort to catalogue and compile political ad buys. At the time, they were only available in paper format and required multiple visits to individual TV stations to acquire. We were part of a group of journalism and public interest organizations convened by Democracy Fund’s Joe Goldman, all of us motivated by a desire to learn more about the big spending “dark money” groups whose tax status precluded them from having to provide regular disclosures to the Federal Election Commission. But they did leave a paper trail when they purchased ads at TV stations, and we were determined to follow it using a combination of technology and legwork — the latter courtesy of volunteers trained by our partners at Free Press.

Then, shortly before the fall 2012 launch of our Political Ad Sleuth website, the FCC won a court ruling requiring broadcast affiliates in the top 50 markets to begin posting ad files online. Using the metadata attached to those FCC files, our developers created a website that enables users to search across TV markets and easily see who is playing in major races, locally and nationally.

The results have been revealing. Having ad buy records available online has enabled our Reporting Group, as well as other journalists, to:

• Unmask the sources of funding behind shadowy nonprofits that can make massive, potentially game-changing last-minute expenditures in a race with little or no regulation from the Federal Election Commission;
• Bring to light otherwise undocumented corporate spending that benefits members of Congress;
• Highlight the entry of a heretofore shadowy Koch brothers’ group in the campaign air wars;
• Document just how early outside groups begin spending in a race. In Kentucky, Senate Minority Leader Mitch McConnell, R, has been under attack from the left and right since February 2013, a full 21 months before he faces the voters in November.

Some of our work, and that of other journalists, informed the brief that Sunlight along with other members of the Public Interest Public Airwaves Coalition filed earlier this year urging the FCC not to back down on its plans to require online filings by all broadcast stations.

It’s important to note that these files have always been public. But until the FCC’s 2012 order, the only way the public could access them was by riding circuit to local TV stations and rooting through paper files.

Why is this important? Some of the biggest money in politics today is being spent completely off the FEC’s radar screen. Television advertisements that mention or depict a candidate and clearly express a point of view about that candidate (like this one ripping McConnell or this one praising Sen. Mark Begich, D-Alaska) don’t have to be reported to the nation’s campaign finance watchdog unless the ads run within 30 days of a primary election or 60 days of a general election. That means a lot elected officials are piling up a lot of IOUs to deep-pocketed donors without the public being able to see — which is why we’re using TV ad files to make them visible.

In Arkansas, where Democratic Sen. Mark Pryor is one of Republicans’ top targets this year, more than 4,000 political ads have been aired since August (subscription required) at a cost of upwards of $2 million. We know this because two reporters from the Arkansas Democrat-Gazette combed through paper files from six stations to compile the information. Sadly, not all TV markets come equipped with such journalistic resources these days, which is why making files available online is important.

At least some smaller market stations appear undaunted by the prospect of online filing. Though they’re not required to begin until this summer, we’ve already seen a filing from a station in Casper, Wyo., notifying a buy from the pro-gay marriage group Freedom to Marry (this is likely the ad in question). And filings have appeared for a station in Cedar Rapids, Iowa, which is seeing a lot of ads for that state’s Senate race.

There’s a lot more to do to make the promise of this transparency a reality. As the broadcasters noted in their brief to the FCC, cable operators don’t have to post their ad buys online, although one major provider already does. As Sunlight has noted, many TV stations allow ad buyers to flout federal disclosure requirements. Last but most definitely not least, the FCC continues to allow the TV stations to post their ad files in hard-to-use PDF format, which means hours of laborious data entry for anyone who actually wants to compute how much a given group has spent in a given market.

Even so, a decision by the FCC to expand its online ad file would give us more — much more — potential for transparency than we have now, and do so just in time for an important election. It’s not a slam-dunk: A top executive for the Gannett broadcasting group told Communications Daily that he still hopes to talk the FCC down.

But if it does happen, it will be a big win for sunlight. As our friends in broadcasting like to say, stay tuned.