The broadcast networks have plenty of headaches. Here's one they probably didn't anticipate: The huge number of viewers cable news networks are luring away with their intensified political coverage.

Cable news ratings are skyrocketing over the drama playing out between senators Hillary Clinton and Barack Obama in the hotly contested, dragged-out race for the Democratic nomination for president.

CNN in February pulled in 883,000 more viewers on an average night than it had in February 2007, with its audience jumping 113 percent. MSNBC had nearly 300,000 more viewers, up 62 percent, and Fox News pulled in 259,000 additional viewers, up 16 percent.

It’s hard to say where these viewers are coming from but it’s a safe bet that a big percentage are migrating from the broadcast networks, which suffered mostly double-digit percentage declines in February.

Network ratings were down for a number of reasons, notably the writers’ strike, which forced the networks to repeat scripted shows. But political was another factor and one that will continue playing out tonight with the coverage of the Texas and Ohio contests, and possibly for several more weeks.

“It’s a very tight race and it’s maybe a lot more interesting and compelling given the lack of scripted dramas on the broadcast networks,” says Shari Anne Brill, senior vice president and director of programming at Carat.

“There’s also a lot of drama in the debates. They’re quite entertaining.”

Tonight is an especially important night, and the cable networks should do especially well as millions tune in as the results of the Texas and Ohio primaries begin rolling out during primetime, along with those of Vermont and Rhode Island. Their outcome could well determine whether Clinton stays in the race.

Ratings could approach those of Super Tuesday, Feb. 5, when about two dozen states held primaries and caucuses.

CNN that night had 3.9 million viewers at its peak, 10 p.m., only 628,000 fewer than CBS had in that time slot. Fox News had 3.7 million viewers at that time and an average 3.5 million for the night. MSNBC peaked at 9 p.m. with 2.3 million viewers and had 2.1 million for the night.

“We’re not expecting the numbers from Super Tuesday but we’re expecting something much better than normal,” says John Spiropoulos, vice president and group research director at MediaVest. “If I had to put a number on it, I’d say somewhere around 80 percent of Super Tuesday numbers.”

The cable news networks’ audiences were even bigger for nights when there were debates. CNN on Jan. 31, for example, pulled in 8.3 million viewers for its democratic debate.

MSNBC’s democratic debate last Tuesday pulled in 7.8 million viewers, its best audience ever.

Perhaps the most remarkable audience bumps for the news networks are in the 18-34 demographic, a group far younger than the typical cable news audience. CNN’s 18-34 audience in February was up 246 percent, with 155,000 more viewers than February 2007. MSNBC was up 109 percent or by 58,000 viewers.

Fox News was up 61 percent or 40,000 viewers, but the Republican-leaning network is benefiting the least from the heated Democratic race.

David Scardino, entertainment specialist at Rubin Postaer and Associates, attributes the rise of CNN and MSNBC to what he calls the Obama factor, referring to Obama’s appeal to young Democratic voters.

“The way the numbers are flowing, particularly with CNN and MSNBC being up more than Fox among the younger Democrats, says to me this is due to new Democrats coming in for Obama,” he says. “You can never prove it but I think it’s the Obama factor.”