The Federal Communications Commission doesn't keep statistics but "is not seeing an increase in political advertising complaints," said Janice Wise, an FCC spokeswoman. She said the FCC has never taken action against a license for the content of ads.
But Oxenford said threats of action — lawsuits or FCC complaints — have risen steadily.
One reason, he said, is the influx of money from corporations and unions this year after the U.S. Supreme Court struck down limits on spending. Under federal law, television stations are required to run political ads, at their lowest rates, from candidates. So courts have held that the stations can't be held responsible for what those ads say.
Independent ads, though, are held to a different standard, and stations could be sued for defamation for airing a false attack.
Sinclair's Faber said it may also be that the threats are "a method people are coming up with to try to combat negative ads."
The complaints aren't always threatening. Last month, Health Care for America Now asked 83 stations to remove ads by 60 Plus Association, attacking Democrats on their health care votes.
"It is within the right of these organizations to run ads, but it is also within the rights of these television stations to at least insist as a matter of accountability that these ads are true," said HCAN's Ethan Rome. No station pulled the ads.
Television ads aren't the only targets. The anti-abortion Susan B. Anthony List planned to erect billboards in three congressional districts held by anti-abortion Democrats, saying their votes for health care law would allow taxpayer-funded abortions.
U.S. Rep. Steve Driehaus, D-Ohio, caught wind of the campaign and complained to the Ohio Elections Commission, which ruled there was probable cause that the billboard constituted a "false claim" under the state's election laws. The billboard company then declined to erect the billboards. The Susan B. Anthony List sued this week in federal court, arguing that the Ohio law is unconstitutional.