Fox News Channel will mark its 10th anniversary this week in an unusual position: knocked back on its heels.

The network is in the midst of its first-ever ratings slump. Cable news' most stable lineup is being juggled. And a blow-up over a confrontational interview with President Clinton by Chris Wallace suggests that Democrats are attacking Fox because they perceive the same vulnerability in the network as they do in the Bush administration.

Loved by some, loathed by others, Fox News Channel has been the biggest success in the cable industry and profoundly changed television news since its signal turned on Oct. 7, 1996.

Fox News chief Roger Ailes can still remember a reporter's laughter during the news conference to introduce the network. He had the last laugh: Fox News beat by a year his plan for overtaking CNN and grew to more than double its rivals in viewership. It made stars of Bill O'Reilly and Sean Hannity and put "fair and balanced" into news history textbooks.

Opinionated talk is now a staple on the TV dial, with Keith Olbermann on MSNBC, Lou Dobbs on CNN and Nancy Grace on CNN Headline News. Fox was first.

Ailes, a former Republican political operative, said presenting different points of view made Fox seem like a contrast to left-leaning news coverage elsewhere.

Fox's critics consider "fair and balanced" camouflage for an agenda. Whatever the truth, news-watching became increasingly partisan: more Democrats watched CNN, more Republicans watched Fox, according to a 2004 study by the Pew Research Center for the People in the Press. The year Fox started, CNN had more Republican viewers than Democrats.

While he cautioned not to overexaggerate Fox's influence, former CBS News President Andrew Heyward suggested industry sensitivity to Fox's popularity, coupled with shock after the Sept. 11 terrorist attacks, combined to dampen aggressiveness in questioning the government's assumptions leading up to the Iraq war. Ailes dismissed that theory with an epithet.

Less attention has been paid to the look of Fox News. During its peak, it appeared more colorful, more graphically innovative and more urgent. It made CNN look stodgy.

But the years of explosive growth have ended at Fox. Viewership over the first eight months of the year was down 5 percent compared to 2005, with a steeper 13 percent decline in prime-time, according to Nielsen Media Research. For 12 straight months, Fox's prime-time audience has been smaller than the year before. Meanwhile, CNN viewership inched up 5 percent this year through August. On a typical day this year, Fox's audience is 845,000, while CNN's is 466,000.

Some of the bigger stories of the past year, such as Hurricane Katrina and the wars in the Middle East, played better to the newsgathering strengths of CNN, Heyward said.

Olbermann's growing popularity — and growing partisanship — along with the response to Clinton's "Fox News Sunday" interview also indicate that Fox's foes have less fear about taking the network on.

Fox has recently made a handful of lineup changes — most notably yanking E.D. Hill from the popular "Fox & Friends" and giving her a daytime anchor slot, replacing her on the morning show with Gretchen Carlson. Ailes said FNC is trying to add some fresh faces to its contributors.

Despite the slump, Ailes is quick to point out that Fox News still consistently beats all competitors throughout the day and evening. "I have to be careful because I'm never satisfied unless we're going upward," he said. "But the truth is, I wouldn't change places with anybody else, and they would change places with me in a heartbeat."