The government shutdown is turning into a major denial of service for journalists and other citizens interested in tracking the influence of big money on politics.

Not only is it preventing scrutiny of campaign finance records — potentially leaving voters in at least one Louisiana special election with NO information on donors before they head to the polls — it’s also making it next to impossible to provide up-to-date information on political ad buys.

The shuttering of the Federal Communications Commission’s website has severely hamstrung Political Ad Sleuth, a tool that the Sunlight Foundation and Free Press developed last year to track those buys at hundreds of TV stations across the country.

And there are plenty of them — some of them attempt to capitalize on the shutdown itself.

We know this because Ad Hawk, our tool for surveillance of political ad videos, shows us examples: The ad “Epic” that the Senate Conservatives Fund has produced in praise of Sen. Ted Cruz, the Texas Republican who is demanding an effective end to President Barack Obama’s health care bill for his vote to fund the government. And the “Games” ad that Terry McAuliffe, a Democrat running for governor in Virginia, has created to tie his GOP opponent to the pro-shutdown Republicans.

But how much is being spent on those ads? And where are the candidates advertising? These are questions that Ad Sleuth has helped us to answer. We built it for two reasons:

• Because of vagaries in campaign finance law, a lot of spending never gets reported to the Federal Election Commission: For instance, there are ads running now in Kentucky that are clearly intended to help or hurt Senate Minority Leader Mitch McConnell’s reelection prospects there. But most of the expenditures will never be accounted for at the FEC because a) the ads don’t explicitly call for a vote for or against McConnell and b) aren’t airing within 30 days of a primary or 60 days of the general election (neither of which occur till next year).
• Since a series of 2010 court decisions — beginning with the Supreme Court’s landmark ruling in Citizens United — lifted limits on corporate spending in elections, there has been a proliferation of vaguely-named political committees, thinly disguised as social welfare non-profits, pouring money into races. In many cases, their agendas and means of support are difficult to identify. The only places they are legally required to leave a paper trail before Election Day:  the television stations where they buy ads.

Ad Sleuth helps solve both problems by putting political ad buy information into a searchable, sortable database that allows journalists and voters to learn more about who is trying to influence elections. Our effort to gather this information was greatly aided when the Federal Communications Commission last year won a court decision that required some 200 stations — those affiliated with the four broadcast networks (ABC, CBS, Fox and NBC) and located in the nation’s top 50 markets — to post their political ad buys to a public website maintained by the FCC. That website helped power Political Ad Sleuth.

Since the shutdown, the FCC is not requiring broadcasters to upload files. Clicking on an Ad Sleuth link to view “original document,” a link that would normally take you to a detailed contract, now directs to the FCC’s shutdown page.

Happily, Sunlight already has recruited volunteers in several TV markets in Virginia — where this year’s only competitive election is being held Nov. 5 — to gather ad files the old-fashioned way: by going to TV stations and copying them. Our intrepid correspondents from Virginia Commonwealth University in Richmond,  the University of Virginia in Charlottesville as well as the Shenandoah Valley are continuing to add to the Ad Sleuth archives, and the files they upload will be available for viewing. And Ad Sleuth can still provide information about who bought ads in what markets up until Monday. But until the government reopens, the links to the original FCC files will remain broken — like so much else in Washington.