From the network’s inception, Roger Ailes has been so synonymous with Fox News that it’s hard to imagine the operation running without the seasoned TV programmer and former Republican political adviser at the helm.

But in the wake of the explosive sexual harassment lawsuit filed against Ailes by former Fox News anchor Gretchen Carlson, the question of succession at Fox News has taken on new urgency. Ailes, 76, is the industry’s highest-ranking TV executive to publicly face legal action on sexual harassment allegations, which have prompted an internal review by parent company 21st Century Fox. (Both 21st Century Fox and Fox News declined to comment for this story.)

It’s no secret that Fox News runs as a separate fiefdom within 21st Century Fox. Fox News is a standalone unit run independently from Fox’s other cable interests. Ailes also oversees the Fox Television Stations division that houses Fox’s 28 O&O stations, which reach more than 37% of U.S. TV households.

Ailes has long wielded major clout with Rupert Murdoch for turning Fox News into a profit center for the company. The Carlson lawsuit comes the same year that Fox News Channel is marking its 20th on-air anniversary. From humble beginnings, Fox News rose in the early 2000s to knock CNN out of the No. 1 spot in cable news, a crown it has yet to surrender. The legal battle will surely test the strength of Ailes’ relationship with James and Lachlan Murdoch, who took the reins of Fox from their father last year. In that transition there was an awkward moment when Ailes indicated that he would not report to James in his new role as CEO. It was ultimately decided that Ailes would report to James and Lachlan as well

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The Fox News culture has routinely been described as familial and populated by staffers who demonstrate great loyalty to and respect for Ailes and the business he built, with one source describing him as a Steve Jobs-like figure. Ailes is beloved by many inside Fox News for his bluntness, his lack of pretense and the lack of bureaucracy and hierarchy within the organization. The 24-hour grind of cable news is grueling, and yet Fox News has by some estimates more than 200 staffers who have been there since the channel’s first days.

Given this atmosphere, it’s doubtful that the parent company would reach outside for a successor, at least in the near term. Multiple sources said the most logical candidate to take the reins from Ailes, if circumstances were to force him to step down as chairman-CEO, would be Bill Shine, Fox News’ senior exec VP who oversees non-news programming for the channel.

Shine has been with FNC virtually since its inception, starting as the producer of “Hannity and Colmes,” the network’s point-counterpoint show. Shine climbed the programming and production ranks and was most recently upped to his current post in 2014.

Jay Wallace is another 20-year Fox News veteran who could rise in authority as he currently oversees all news programming and newsgathering operations as exec VP of news and editorial. He worked his way up from the entry level job of tape coordinator. Wallace could gain more turf in a post-Ailes restructuring, sources said, but ultimately Shine is seen by insiders as the most likely choice for the top job given his managerial experience and the temperament for the job of wrangling disparate staff members and talent. Wallace is well-liked internally but was just promoted in April to the top news post.

Given Ailes’ popularity at Fox News, it remains to be seen how the internal review  — and the fallout from Carlson’s suit — will impact his standing at the network. Carlson’s suit prompted six other women to come forward this past weekend with allegations about sexually charged encounters with Ailes dating back to the 1960s, ’70s and ’80s, although only two went on the record to New York magazine with their full names.

At the same time, Fox News correspondents —- including Maria Bartiromo, Ainsley Earhardt, Martha MacCallum, Harris Faulkner and Greta Van Susteren — have spoken out in support of Ailes, along with many other staffers who have demonstrated support for the boss in his hour of need, according to sources. Megyn Kelly, Fox’s brightest female star at the moment, has publicly kept silent.