Walsh pointed to Phoenix, a television market that could have as many as five competitive Congressional elections, a competitive Senate seat and even a battle for the state’s 12 electoral votes. President Obama’s campaign strategists have indicated they believe Arizona’s growing Hispanic community will put the state in play this year.

If each campaign must pay $280 per gross ratings point on broadcast television, few are going to be able to sustain that spending throughout the voting period.

“How many Congressional, or even Senate, campaigns are going to have those kinds of resources at their disposal?” Walsh asked. Instead of a prolonged broadcast blitz, cable will become a more affordable answer.

Strategists who specialize in placing advertisements on television are finding it necessary to reconsider their methods thanks to rapidly evolving technology that is changing the way Americans consume media, broadly speaking, and watch television, more specifically. Industry research shows television viewership is rapidly declining; viewership this season is down almost 10 million over last season as more Americans begin watching programs on digital video recorders (DVRs) and on internet video-on-demand sites like Hulu.

DVRs are increasingly making their way into American households. Fully 44 percent of consumers have a DVR, up from 33 percent in 2008, according to Deloitte’s annual State of the Media Democracy survey released in early January. Meanwhile, almost one in ten consumers have canceled their paid television service because they can watch their preferred shows online, the survey found, while 15 percent say they will most likely watch all their television online in the near future. The percentage who say they will watch their favorite shows live, as they air on television, has dropped precipitously, from 87 percent in 2008 to 71 percent this year. Among the Millenial generation, those between 23 and 28 years old, the number who will watch television live—and thus sit through political commercials—falls to 59 percent.

Crawford, of JDA Frontline, sees the growth of Internet and DVR technologies as an opportunity to reach more voters in more targeted media. “The DVR allows us to reach more people through television advertising than we would have without it. As for those who choose to fast-forward through advertising, the ads are retained even if the viewer is fast-forwarding at the fastest rate,” Crawford says.

Ads in the last minute before a show comes back on are best positioned, given a viewer’s habit of pressing play before a commercial break ends. And, says NCC Media’s Kay, the types of programming people watch on cable are different from shows that do well on broadcast. While the average consumer might record a hit primetime show or a sporting event, they are much less likely to record something on the Food Network, which broadcasts hours of the same type of programming.

“It’s not appointment viewing,” says Kay.

DVRs have yet to reach the stage some advertising companies feared they would; Crawford says five years ago, some of those firms believed the DVR would make them obsolete. But habits are hard to break, and consumers still overwhelmingly prefer to view their favorite shows in real time.

But the evolution of technology means more campaigns will begin doing what President Obama’s campaign did in 2008—advertising in non-traditional venues like video games, Hulu and elsewhere. Four years ago, Obama’s campaign had such a large ad budget that they advertised in video games like Madden NFL ‘09 and several others in which users connect to an online service. The campaign was able to target users in 10 swing states, and the ads appeared as signage in sports stadiums.

This year, online advertising is already widespread, thanks to Google’s AdWords program and others, and Romney’s campaign has advertised widely on YouTube. J.B. Poersch, a strategist who ran the Democratic Senatorial Campaign Committee for three cycles, says he expects campaigns to reserve more than 10 percent of their overall budgets for other social and nontraditional media efforts.

Party strategists on both sides are taking more care with their advertising money, even as the amount of money available to a campaign balloons. Finding the right programs and the right persuadable viewers within the right window may make the difference between a win or a loss—and, with the Senate so narrowly divided and the House potentially in play, it may mean the perfectly-timed surgical strike or the right kind of sustained outreach could wind up determining which party sends a majority to Washington.

Stay tuned for what’s certain to be a long, and crucial, commercial break.

Reid Wilson is editor-in-chief of National Journal Hotline.