NORTH MANKATO — The origin of the money behind Americans for Prosperity is hidden. Its destination isn’t: television viewers watching everything from “The Price is Right” to the local news to the “Late Show with David Letterman.”

Americans for Prosperity, a conservative political organization that opposes the re-election of Democratic President Barack Obama, has purchased nearly $31 million in advertising time already from TV stations across America, reports the Center for Responsive Politics.

Even North Mankato’s KEYC-TV, in a non-battleground-state like Minnesota, received nearly $175,000 from Americans for Prosperity to run anti-Obama advertisements more than 800 times starting in late July and ending Monday, according to public disclosure paperwork filed by the station.

Americans for Prosperity, which doesn’t reveal the names of its donors but was founded by the billionaire brothers David and Charles Koch, was easily the biggest campaign ad buyer at KEYC so far in the 2012 campaign season. But the tidal wave is likely still coming.

The next wave

Minnesotans for Marriage is planning to air 367 30-second ads on KEYC supporting the marriage amendment voters will face on the state’s general election ballot. Kicking off its ads locally Oct. 1, Minnesotans for Marriage is set to run them through Nov. 6 — the day of the election.

The primary supporter of the constitutional amendment to reinforce the state’s existing prohibition of same-sex marriage, the organization is scheduling its ads throughout the CBS affiliate’s varied programming but with a particular focus on local newscasts.

The station also owns the local Fox affiliate “Fox Mankato” and Minnesotans for Marriage will attempt to reach sports fans there, running pro-amendment ads 52 times — including during NFL games and the Major League Baseball postseason in October and early November.

The combined price of the ads on the two channels totals $75,000.

The Minnesotans for Marriage ads are the only ad buys currently in place at KEYC/Fox Mankato for the final eight weeks of the campaign, although station Vice President and General Manager Denny Wahlstrom said purchases are commonly made at the last minute.

“It should be a good year,” Wahlstrom said. “Typically, political spending has fared pretty well in the Mankato market.”

Tight races, loose spending

KEYC doesn’t have local competitors for a wide swath of south-central and southwestern Minnesota, along with a piece of northern Iowa. That makes the station a natural target for candidates running for southern Minnesota’s 1st Congressional District or special interest groups that see the region’s voters as having the potential to swing the outcome on other parts of the ballot.

Democratic Congressman Tim Walz of Mankato is currently seen as a safe bet for re-election, however, as is Democratic Sen. Amy Klobuchar. Those races would have to tighten up over the next month for KEYC to have a bumper crop of political ads.

“I think the area has had more highly contested races in the past,” Wahlstrom said.

Walz proved in 2006 that a race — and the pace of TV ad purchases — can change dramatically in the final weeks. Attempting to knock off 12-year incumbent Congressman Gil Gutknecht, Walz saw donations pour into his campaign when it became clear he had a chance for the upset.

And the Republican Party, suddenly worried about Gutknecht, flooded the district’s TV markets with ads of their own — leaving KEYC viewers to face an endless deluge of 1st District advertising in the final days of the campaign.

The big bucks

Even a competitive congressional race in southern Minnesota might generate $2 million or $3 million of spending. The presidential campaigns, when outside interest groups are included, will burn through billions with most of it concentrated on 10 or so swing states. To the detriment of Gopher State TV stations, Minnesota won’t be one of them.

The most reliably Democratic state in the nation in presidential elections the past three decades, Minnesota looks to be an afterthought in 2012 after Republicans thought the state might be trending their way in 2004 and 2008.

Iowa, by contrast, is a targeted race by both Mitt Romney and Obama. So Wahlstrom is hoping the six counties the station reaches in Iowa can draw some money to KEYC out of the overflowing presidential campaign treasuries.

“We’re trying to get them to come to us for northern Iowa,” he said.

No promises

In any case, as ad buys from Americans for Prosperity and Minnesotans for Marriage demonstrate, election years are good for the bottom line at KEYC.

Political ads to be run by Minnesotans for Marriage on Fox Mankato cost as little as $35 during programming that draws small audiences, but the price rises to $425 for 30 seconds during NFL games. Spots running during KEYC’s 6 p.m. and 10 p.m. newscasts go for $500 and $525, respectively.

So with all that money flowing in, will news anchors Lisa Cownie and Dion Cheney be seen in KEYC Ferraris rather than the current fleet of mini-SUVs? Will Mark Tarello — the station’s alliteration-addicted ace of atmospheric augury — be getting a mess of meteorological machinery? How about Perry Dyke reading high school scores in a different Armani suit for each week of the winter sports season?

“No, no, no, no, no,” Wahlstrom said of the influx of campaign revenue. “We usually end up buying high-definition equipment with that. So it’s usually something like Sony or Panasonic (that benefits).”

While campaign spending is a “significant” boost to KEYC’s income in election years, campaign ads aren’t exactly viewer favorites. By the final days of a particularly vicious campaign, Americans regularly threaten to turn their TV set off for fear of beaning it with a heavy object if they have to watch any more mud fly.

Wahlstrom said ads that stretch the truth to the breaking point can be problematic for the station, which sometimes has to ask buyers to provide documentation of claims.

“If we have reservations, we typically will ask the agency/candidate/third party for proof,” he said. “But many of these are gray areas.”

Only once was the claim so clearly wrong that the station refused to continue airing a political ad. That one, Wahlstrom recalled, involved a third-party attack ad against Gutknecht.

As for viewer exasperation with the unending onslaught of ads in October, the good news is that the candidates and the parties and the special interest groups get the blame.

“They don’t really blame us,” Wahlstrom said of viewers. “They don’t shoot the messenger.”