Just as the Minnesota gubernatorial race heats up, KSTP-TV and WCCO-TV will not report how much third-party groups such as Alliance for a Better Minnesota and MnForward spend buying ads on each station.

Political reporters mine each station’s “political file” for data on campaign spending and strategy. The figures are available months before the groups file campaign finance reports, and contain more detail. For several elections, MPR has used political files to construct a great ad-spending database.

The issue is especially meaningful in recent days, with news that KSTP owner Hubbard Broadcasting, Inc. helps fund MnForward, a pro-Tom Emmer group buying ads on KSTP and other stations. MnForward is taking advantage of a recent Supreme Court decision allowing corporations to fund ads directly advocating a politician’s election.

Hoping to see how quickly HBI’s donation was repaid in ad spending, I first asked Brian McClung, who directs MnForward. He declined to detail the group’s purchases - suggesting I look at the political file. But a stop at KSTP Tuesday revealed the station only reports figures for federal issue advertising.

That means that HBI won’t say how much it gets from a group HBI funds.

However, KSTP is not alone. CBS-owned WCCO, which regularly reported independent-group payments, stopped in recent days.

WCCO communications director Kiki Rosatti explains, “We recently became aware that only national issue advertising requires us to place pricing in the public file. With regards to local issue advertising, we are required to include the political inquiry form. This form identifies the account name, the ad agency, and who is paying for it. Each of our local issue ads has a political inquiry form in the public file.”

Rosatti says no group requested the policy change, which happened after an internal review of campaign finance laws.

For now, KARE11 and Fox9 continue to report interest-group spending, as does Comcast Cable. KSTP’s refusal means spending on KSTC-Channel 45 and KSAX/KRWF in western Minnesota will remain opaque; WCCO’s decision also affects ads on Alexandria’s KCCO-TV.

By going dark, the TV stations are acting like any other corporation that can refuse details of its political receipts. However, other corporations don’t operate on the public airwaves. As the Federal Communications Commission notes:

In exchange for obtaining a valuable license to operate a broadcast station using the public airwaves, each radio and television licensee is required by law to operate its station in the “public interest, convenience and necessity.” This means that it must air programming that is responsive to the needs and problems of its local community of license.

One way to gauge that: the political file, which provides public accountability on whether stations comply with FCC rules regarding equal access and pricing. (In other words, political ads aren’t like those for soap and cars.)

According to the FCC, stations must keep a file that if an ad “communicates a message relating to any political matter of national importance.” Stations must “identify how the station responded to such requests and, if the request was granted, the charges made, a schedule of time purchased, the times the spots actually aired, the rates charged, and the classes of time purchased. The file also must reflect any free time provided to a candidate. The station must keep the political records in the file for two years after the spot airs.”

Obviously, KSTP and WCCO believe there’s no state requirement for the same sort of transparency.

Rosatti says spending amounts are still provided for all candidates, including state and local ones. But third-party groups such as the Alliance for a Better Minnesota and MnForward may spend more than any gubernatorial campaign, leaving a major accountability hole.

With TV stations opting out, would Minnesota lawmakers vote to bring FCC-level disclosure to state and local races? Well, reporters aren’t the only ones who look at the political file - anyone can, including political rivals. If more politicians benefit from obfuscation than disclosure, don’t bet on anything changing. We’ll have to rely on the public-spiritedness of the stations that still report the full details.