Tim Higgins of Bloomberg Businessweek offers an answer.

As what promises to be the most expensive presidential election in U.S. history heats up, one constituency is dreading the coming barrage of political advertising perhaps more than any other: car dealers.

In some battleground markets, a presidential race can soak up a third or more of local broadcast television advertising time, crowding out auto dealers, who are typically the biggest buyers of local TV ad time, according to a Bloomberg analysis. That shift, according to the analysis of data from Kantar Media Intelligence, CMAG, and Kelley Blue Book, can hurt sales.

Take Cleveland, for example, a major battleground in the 2012 campaign. The number of car ads that ran on local broadcast stations in October 2012, the final month of the race, fell to 4,553, a 16 percent drop compared to the same month a year earlier, while the number of political ads soared to more than 27,000 that month alone, according to the analysis. Actual car and light truck sales rose just 5 percent even as the nation rose 16 percent, according to data from Kelley Blue Book.

The flood of political commercials on broadcast TV in 2012, which bumped car ads off the air in local markets across the U.S., may have slowed the rise of new auto sales on average by 1 percent in September 2012 and 1.5 percent in October 2012 and could have been three times as much in the most intensely targeted political markets, according to the analysis, which was conducted by Ken Goldstein, a professor at University of San Francisco and an analyst for Bloomberg Politics, and Carly Urban, an economics professor at Montana State University.

Of course, in some cases, an auto company losing business because of politics would amount to poetic justice.