The candidates, pundits and anchors are not the only ones fighting for screen time during the recent presidential debates.
Cable news networks are now frequently running commercials during special events in a large box alongside a smaller image of their coverage. In the two hours leading up to the first presidential debate on Sept. 26, Fox News Channel showed commercials for big-name advertisers such as FedEx and General Motors on two-thirds of the screen while viewers were also able to keep an eye on the hubbub at Hofstra University before Hillary Clinton and Donald Trump faced off.
The networks' thinking is that as long as there is program content on the screen, viewers will be less likely to switch channels.
Not every advertiser agrees to run in the dual screen breaks, which the television industry calls a "squeeze back." But many are willing to try the format, which viewers will see again Sunday when Clinton and Trump meet for their second debate at Washington University in St. Louis.
"Some of them feel strongly that they are paying for full screen and if that's what they want, we make sure that's what happens," said Paul Rittenberg, executive vice president of national sales and marketing for Fox News Channel. "Others don't care and accept the argument that 'Hey, this is a win for you, because if we cut entirely to a commercial people are going to flip to another channel, because this thing is all over the place and this is a way to keep the viewer on the screen.' "
Fox News, CNN and MSNBC also used squeeze backs during the primary nights, when tabulated voting results could be shown in a box alongside commercials. Viewers can expect to see them on election night as well.
CNN declined to comment on its use of the format, but one executive who spoke on condition of anonymity said the minute-by-minute Nielsen ratings show that viewers switch away in droves during commercial breaks, so the network has to be willing to innovate.
Cable news started using squeeze backs during coverage of the 2012 presidential campaign season. But the format first evolved in sports TV around 2009, when ESPN introduced it during IndyCar race telecasts, which had no natural breaks for commercials. At the time ESPN called the format "side-by-side."
"It was designed to keep you watching while the race was still going," said Ed Erhardt, president of global sales and marketing for ESPN. "Most of the advertisers were comfortable, with a little cajoling."
The format was quickly adopted throughout financial news coverage and on weather forecasts. Cable news is using the format more often, pointing to a possible future in which program content, data and ad messages are often simultaneous displayed.
"I think you're going to see more occasions when the screen will be shared," Erhardt said.
Although advertisers are willing to use squeeze backs, their effectiveness is still being debated.
"There's both pros and cons to squeeze backs in that a cluttered environment is not optimum for getting a brand message across," said Billie Gold, vice president and director of programming research for Amplifi US, a media-buying firm. "However, with an ad in view during important content, attentiveness, recall and visibility may increase."
The growing use of squeeze backs signals how the TV audience is less tolerant of commercials in general, the result of spending more time watching ad-free streaming video services like Netflix. Consumers also have grown accustomed to skipping through breaks when playing back shows on their DVRs.
Many cable networks, such as those owned by Turner Broadcasting and Viacom, have shortened their commercial breaks in recent years in response to the trend.
When viewers are forced to sit through commercials for live events — the only time that they still have to — they're often not happy. Many Olympics fans took to social media to vent about NBC's ad interruptions during its coverage of the Rio Games this summer. But data showed that the network had run the same number of spots per hour during the London Games in 2012.
Network executives acknowledge that some viewers find the squeeze backs annoying as well. It's why Erhardt believes that it's wise for networks that use the format to make viewers aware that it is a way to limit interruptions.
NBC Sports did just that by promoting its use of squeeze backs for 40% of the commercials it showed during its recent Ryder Cup golf tournament coverage. The network even gave the format a golf-oriented name, "Playing Through."
Strong ratings during the presidential campaign are a big factor in helping cable news networks persuade advertisers to go along with squeeze backs. The edition of Fox News Channel's "The O'Reilly Factor" that preceded the Sept. 26 debate averaged 4.8 million viewers, nearly 2 million more than the program draws on a typical night. Advertising categories such as beer and movies, which rarely buy time on cable news, have shown up on the debates.
"There is enough demand that we could jam [squeeze backs] through if people were opposed to it," Rittenberg said. "More than half of them are willing to roll with it because it's a big rating."