Imagine this scenario: you’re in charge of an issue campaign opposing Pennsylvania Sen. Bob Casey’s (D) reelection. You got a bit of a late start, but still managed to raise a good chunk of change in the form of unlimited contributions through a Super PAC. Now you’re looking to buy some media time on WPXI—the NBC affiliate in Pittsburgh.

Media buyers like WPXI. It reaches a myriad of the state’s coal mining towns in Pennsylvania’s heavily unionized, but traditionally conservative, southwest. So you call up Sales Manager Cedric Thomas to ask about a flight of ads during the station’s news shows. Thomas doesn’t even bother with the rate card.

“Sold out,” he says. He sounds sympathetic, but says there’s nothing he can do.

Maybe there’s an episode of “The Mentalist” with an empty slot? Another primetime show, perhaps? “Afraid not,” Thomas says. “Once you’re sold out, you’re out.” Trying not to panic, you nonetheless feel a little like you’re at the supermarket shopping for hurricane supplies and finding only empty shelves where the batteries and water once were.

Get used to it, consultants and station managers warn. Airtime scarcity will be more of an issue in 2012 than ever before.

After the Supreme Court’s Citizens United decision, and with more than 300 Super PACs preparing to take to the airwaves against the backdrop of a presidential campaign that could very well pit the two best funded candidates in history against one another, the vital commodity of broadcast TV time could be hard to find.

“I believe this will be a record-setting year,” says Thomas. “In the battleground states, running out of inventory is a possibility.”

Does all of that sound just a bit far-fetched? Perhaps you’re thinking back to the not-so-distant past before McCain-Feingold and assuming this cycle will just resemble the soft money days?  

“I think it’s unclear because no one’s really bought yet for the cycle,” argues Democratic media strategist Jon Vogel, a former executive director of the Democratic Congressional Campaign Committee who isn’t yet convinced that 2012 will result in such a drastic run on airtime.

But consider this: By early February of this year, Super PACs had reported spending almost $50 million since January. Two of the largest Republican issue groups, Crossroads GPS and Americans for Prosperity, spent more than $8.7 million combined in just two weeks during the first month of the year. Their spots ran on broadcast and cable TV, from Albuquerque, N.M. to Wilkes-Barre, Pa.

President Obama’s campaign responded with an early barrage of its own, running more than 2,500 spots in 10 targeted media markets, according to an analysis by Wesleyan University and CMAG. 

“[The Obama campaign is] responding rather quickly to what the Super PACs are doing,” says Travis Ridout, a Washington State University professor who co-directs the Wesleyan/CMAG ad monitoring project. “It’s possible we’ll see ads running from now until Election Day.”

While the amount being spent in the GOP presidential primary is similar to what was dished out in 2008, there’s a big difference. Ads run by issue groups went from the low single digits in 2008 to totaling nearly half of all airings today, according to Ridout’s group. These are the folks who are going to be competing for the limited amount of broadcast airtime in battleground states come the fall.

President Obama and federal candidates like Casey don’t have to worry about an end-of-airtime scenario. The Federal Communications Commission ensures that all federal candidates can have access to the airwaves, even if they have to pay a premium during a busy campaign season. Down ballot candidates and issue groups, though, aren’t protected by the same most-favored-advertiser status. They can be bumped to less favorable ad times, have their ads dropped for other content, or told that there isn’t room for them on the airwaves.

This isn’t to suggest that groups with money to spend won’t be able to get on TV. Ad sales managers such as Thomas wield their inventory well. They can often shuffle their lineups to push spots for local car dealers and mattress wholesalers past Election Day to make room. Plus, there are always slots available during the daytime schedule, or on radio, cable or online. Even so, broadcast television remains the most efficient mass medium, and there’s only so much inventory stations can sell.

“The battleground states haven’t changed and there are competitive elections across the board,” says Paul Winn, a Republican media strategist. “Traditional inventory in these states is going to be sold out and we’re going to see the overflow go” to online, cable and radio.

January 2010 saw the birth of the forces that shape today’s media environment. The special election race in Massachusetts that month to succeed the late Sen. Ted Kennedy was the first time, consultants and station managers say, that a burst of political ad spending cleaned out the prime inventory in a large media market.

Thanks to the emotion involved, and the Kennedy legacy, the race was widely regarded as a foregone conclusion in its early stages. But polls released two weeks before the vote showed then-state Sen. Scott Brown (R) gaining ground on Democrat Martha Coakley. The resulting spending spree produced a run on inventory for NBC, CBS and ABC affiliates in Boston. The dollars that were thrown around has become the stuff of legend in New England.

“It was the heaviest volume in a short period of time that I’ve seen in this market,” says Andy Hoffman, general sales manager with WCVB, Boston’s ABC affiliate. “All of a sudden, when the polling came out, that’s when the money just flowed in in very large volumes.”

Hoffman, who has worked in the Boston market for 30 years, says he has never seen anything like it before. “We completely sold out in our key newscasts,” he recalls. “So much money had to be spent so fast.”

The issue groups that sought to influence the race’s outcome were still able to get up on the city’s FOX affiliate and the cable networks—in addition to some buys that were converted to radio—but the prime news spots on broadcast were all spoken for. 

Brown won the Jan. 19 vote and two days later, the Supreme Court ruled in the Citizens United case that corporations and unions could raise and spend unlimited funds on independent expenditures. Had that ruling come down earlier, it could have created an even more frenzied scenario in Massachusetts, with well-funded Super PACs lined up on both sides. With that in mind, Brown and Democrat Elizabeth Warren have pledged to keep Super PACs out of their Senate race. Station ad managers like Hoffman are waiting to see if they’re successful.

One of the states that will be at the heart of the coming TV ad spending storm is Virginia. It’s a target for the Obama campaign, which is looking to repeat the president’s 2008 success there. And in addition to its usual medley of competitive House races, it also plays host to one of the highest profile Senate races this cycle between former Democratic National Committee Chairman Tim Kaine and former Sen. George Allen (R).

Millions are expected to pour into the state’s media markets. TV ad buyers looking to get on, say, a small-market CBS affiliate in Virginia will be competing for about 1,100 weekly 30-second spots on its early and evening news programs, according to a rate card shown to C&E.

“It’s going to be the wild, wild West in terms of TV and media buying,” predicts John Rowley, a Democratic media buyer. Like Winn, Rowley sees the overflow going to, what until now, have been considered less efficient mediums. “I think we’ll definitely have a record setting year in terms of online,” says Rowley. 

Online can certainly work as an alternative, says GOP media strategist Will Feltus. But Feltus argues that online is a way of preaching to the choir, not persuading voters. Rather, Feltus says, radio, which some politicos consider a medium akin to telegramming voters, will make a comeback in 2012.

“Radio gets you outside the clutter,” he says. “If I hear it on radio and then I see it on TV, maybe I don’t have to see it as often.”

Cable buys, he says, will also need to be deeper in order to make up the ratings points unavailable on broadcast. “You can replicate the audience on cable, but it’s a different kind of media buying,” he says. “Smart cable media buys go down 12 or 20 channels deep.”

Messaging will also be a challenge amid the cacophony of political advertising in 2012. There’s no doubt that targeted markets will see political spots sandwiched up against one another. Newscast station breaks with nothing but political messages will be the norm. The vast majority of these ads are expected to be negative – dark colors, deep voiceover, accusations of malfeasance. Voters will become desensitized and it’ll be a challenge for candidates to break through.

Rowley, who consultants for many House candidates, thinks campaigns can actually stand out more in this cycle’s environment by being upbeat. “Frankly, a candidate’s campaign lends itself to being positive.”

Using different creative techniques is another option. Strategists like Fred Davis have made careers out of producing ads that stand out. Davis produced the online “Demon Sheep” video for California Republican Carly Fiorina and the “danged fence” spot for Sen. John McCain in 2010 that generated national news. (The ad Davis produced for former Rep. Pete Hoekstra’s campaign recently made headlines for an altogether different reason, but it certainly stood out.)

Jon Vogel is one who thinks there’s no need to reinvent the wheel in 2012. “I think candidate-to-camera actually has a lot of impact when there’s a lot of studio garbage getting thrown around,” says Vogel, who consulted for House Majority PAC during its ad campaign in the 2011 New York special election that produced a surprise win for Democrat Kathy Hochul.

But for issue groups that must support or oppose in their messaging, there’s less room to distinguish the creative.

Getting a message heard is just one of the challenges for advertisers this cycle. Candidates face the added hurdle of weighing whether to join in with a super PAC that is attacking their opponent. Coordination, we know, is illegal but candidates can compound the message of a supportive Super PAC by mirroring its advertising.

“You almost have to pile of top of it,” says Rowley. “[Candidates and groups] see what the other is putting out on their website. It’s not really coordination so much as taking in the public information that’s available.”

Perhaps the best option for cutting through the crowded ideas marketplace is buying early. Conventional wisdom is that voters have a short attention span so buying early is an inefficient use of resources. Winn says that logic will flip in 2012 given the new landscape.

“Any money you spend in early September is going to go a lot further than in late October,” he says. The bottom line, he adds, is that “if you’re a candidate, you’re probably going to be alright. If you’re an issue group, you’re going to have to get more creative.”

Back in Pittsburgh, Cedric Thomas is preparing for the coming deluge. Groups and candidates aren’t booking yet for the fall—the GOP primary remains the focus—but Thomas is waiting for his phone to start ringing.

“They should probably book sooner than later,” he says about issue groups. “I have my rate card ready. We’re set.”

Sean J. Miller is a contributing editor to Campaigns & Elections.