NEW YORK (AP) — Watch Bill O'Reilly and Keith Olbermann on the same night and you'll swear they're talking about two different presidential campaigns.

At 8 o'clock each weeknight, the two men survey the McCain-Obama competition from opposite mountaintops, as kings of cable's opinion class. They're the beneficiaries of an increased desire by news viewers to follow stories through their own ideological filters.

Things may quiet down after Election Day, but that trend likely won't be reversed.

O'Reilly, who last week announced he'd signed a multiyear contract to stick with Fox News Channel, is on pace to have his third most-watched month ever with four million viewers a night. September was second. Fox has also locked up conservative prime-time star Sean Hannity to a contract extension.

Olbermann has hit milestones this month — on October 14 his largest audience since "Countdown" started in April 2003, and on Tuesday his biggest in a key youthful demographic. Rachel Maddow, Olbermann's political soul mate, has been an instant hit since her 9 p.m. show started in September.

Together, their liberal two-hour block is averaging just under two million viewers a night this month on MSNBC, compared to the 576,000 for Olbermann and Dan Abrams in October 2007, according to Nielsen Media Research.

Left with the wide middle at 8 p.m. on CNN, Campbell Brown has become more assertive with opinions, criticizing the McCain campaign for "sexist" treatment of Sarah Palin in guarding her from reporters.

During a "typical" night on Wednesday, Olbermann and O'Reilly's agendas rarely intersected, except when discussing news that the Republican Party had spent $150,000 in clothes and accessories for Sarah Palin and her family from high-end stores like Saks Fifth Avenue and Neiman Marcus.

Olbermann made it the subject of his commentary, saying the American public had "completely seen through" the McCain campaign.

"Nothing could say disconnect faster — you trying to pin your opponent with the phrase 'share the wealth,' while your campaign gets pinned for having shared $150,000 of wealth with two of the ritziest clothing stores in the country to dress up your running mate," Olbermann said.

O'Reilly and his guest, Laura Ingraham, condemned NBC News for reporting about the spending ("they're a joke," Ingraham said). She said the same people critical of the spending would say Palin looked like "white trash" without the new clothes.

"Sarah Palin has adopted Barack Obama's campaign mantra," O'Reilly said. "She is spreading the wealth around."

Ingraham broke up in laughter. Besides the conservative talk show host Ingraham, O'Reilly's guests included Byron York of the conservative magazine National Review, comic Dennis Miller saying how proud he is to vote for McCain, and Republican Minnesota Rep. Michele Bachmann, in the news for questioning whether some Democrats were pro-America. That's not to say he doesn't invite guests he disagrees with; he had a memorably skeptical interview with Obama in September.

Olbermann has emerged as a pressure valve for liberal voters angry after eight years with President Bush, the steam turned up as the election approaches. It's hard to imagine him interviewing McCain and, judging by how the Republican rolled his eyes when David Letterman mentioned his name recently, even tougher to imagine McCain wanting to speak to him.

The two hosts share an antipathy and, frankly, obsession with each other. O'Reilly never mentions Olbermann's name, but attacks NBC relentlessly. "It's the usual for NBC News," he said about Andrea Mitchell's reporting on the clothing story, "trying to diminish the McCain-Palin ticket in any way they can."

He listened with sympathy to Bachmann, who claimed her damaging quote was the result of a "trap" set by MSNBC's Chris Matthews.

Olbermann bragged about how he and Maddow topped O'Reilly the night before among viewers aged 25-to-54 (NBC essentially ignores older viewers, considering them unattractive to advertisers; O'Reilly dominates that audience).

"Happy new contract, Bill," he said, with the song "Celebration" in the background. "We hope you'll enjoy every minute of those four years in third place."

The increased popularity of the opinionated shows has one newsman concerned about viewers retreating into their own cocoons. People need to be challenged with different views, and they're likely to have fewer opportunities to do so with programs like "Countdown" and "The O'Reilly Factor" making money for their networks, said Rome Hartman, executive producer of BBC's "World News America."

"If you have a business culture where the boss says one thing and everybody toes the line and says 'Boy, boss, that's right, you're right,' well, that's a business that's not going to last very long," he said.

O'Reilly led Wednesday's telecast with the story of CNN reporter Drew Griffin falsely suggesting, during an interview with Sarah Palin, that the National Review's York had called her incompetent or unqualified. Instead, York was commenting on how others had said that about her. O'Reilly was outraged.