In a November ad for their special series “Fox News Reporting: The Challengers for 2012,” Fox News promised “unrivaled access” to “the GOP's top White House contenders.” Such access, however, isn't hard when correspondents just have to walk down the hall.

That Fox News helps Republicans get their message across to their conservative base -- long documented and publicly acknowledged by Republican officials -- is nothing new. But what's unprecedented is the level of influence one news organization can exert on a party's presidential primary, and the rest of the media's coverage of that primary, by simple fact of who is on its payroll.

Fox News employs five Republicans considering runs for the GOP nomination: Sarah Palin, Mike Huckabee, Newt Gingrich, Rick Santorum and John Bolton. All five regularly appear on the network through exclusive contracts and all five have used their employment to position themselves for their respective possible runs.

Take the cases of Rick Santorum and John Bolton -- two potential candidates who have so little chance of winning the nomination that Fox didn't even include them in their twelve challenger profiles.

Both would largely be out of the public spotlight if not for their Fox News contracts, yet Santorum -- who lost his Senate seat to Bob Casey (D-PA) by 17 points in 2006 -- has appeared on the Fox programs America's Nightly Scoreboard (twice), America's Newsroom (twice), The Willis Report (twice), America Live, On the Record (twice) and Varney & Company (twice, as a “special guest”) in the past two weeks.

During the same time, Bolton has appeared as a foreign policy and national security expert on America's News HQ (where he has a regular slot), Follow The Money, America's Newsroom (twice), America Live, Fox & Friends, Hannity, On the Record, and Varney & Company (as a “special guest”!).

On the other side of the spectrum is Sarah Palin, who has little trouble attracting attention. But as her TLC program and public comments indicate, Palin prefers a certain type of attention in which she can tightly control the messaging. It's no wonder then that her media appearances have mostly come within the friendly confines of Fox News, where she can pass on debunked theories and pal around with conservative opinion makers like Sean Hannity and Glenn Beck.

After leaving public office in disgrace, Newt Gingrich signed his “first television deal since leaving Congress” with Fox News in 1999. Since then, Fox News has treated him like royalty during his attempted rehabilitation. Gingrich has hosted Fox News Specials on college costs, religion, international gangs and bird flu (yes, bird flu). On one day in 2009, Fox dispatched a reporter to provide round-the-clock coverage to a Gingrich-convened “Jobs Summit.” Last year, during a typical softball interview, a Fox “straight news” program directed viewers to Gingrich's GOP tour and website.

Mike Huckabee is the only Fox candidate with a regularly scheduled show, the weekend talker Huckabee. Huckabee's show has always been closely tied to his political machine: the show was first announced in a statement posted on his political action committee and, according to the New York Post (via Nexis), “not, as is customary, from the network.”

Since then, Huckabee has unsurprisingly used his program to position himself for a potential political run. The former Arkansas governor has used Fox News' airwaves to grow his PAC and email lists directly (he touted the address of an email catcher website run by his PAC) and indirectly, through regular solicitations to give “feedback” to MikeHuckabee.com, which conveniently links to his PAC and an email signup page. Huckabee has also used his program's guest list as an extension of his PAC.

But why wouldn't Huckabee run? Again, Fox News' influence comes into play.

In November 2009, Huckabee remarked on Fox News Sunday that if he doesn't run for president, it's because “this Fox gig I got right now” is “really, really wonderful.” Last month, conservative columnist Jonah Goldberg wrote that there's “growing buzz” that Huckabee “may not run because he's got a big new contract with Fox News in the works” (a Huckabee aide responded that there were no Fox talks). Financial considerations could also come into play for Palin, who reportedly makes $1 million a year with Fox News.

According to Politico, Fox “indicated that once any of the candidates declares for the presidency he or she will have to sever the deal with the network.” ABC's George Stephanopoulos noted that the Fox candidates may actually delay their announcements to reap the benefits of the Fox cocoon for as long as possible. Reporter Claire Shipman replied that Fox's “very healthy platform” allows the Fox candidates to keep visible without spending money early.

The potential delay of their “official” announcements means that the Fox candidates can also compile staff and resources while still cashing a paycheck.

Huckabee, Palin and Gingrich have Fox-promoted groups ready to convert to campaign mode if each chooses to run. Santorum has already hired a staff member (for his PAC) in the important primary state of New Hampshire and, according to the New Hampshire Union Leader, is “expected to formally” announce “in the spring.” And Bolton is reportedly “very serious about a presidential bid and has begun to speak with potential staff.”

During this non-“official” period, the Fox candidates can also cite their Fox contract as a reason to decline appearances on other news organizations who may offer a tougher environment than Fox (a low bar). Indeed, Politico reported that “C-SPAN Political Editor Steve Scully said that when C-SPAN tried to have Palin on for an interview, he was told he had to first get Fox's permission -- which the network, citing her contract, ultimately denied. Producers at NBC, ABC, CBS, CNN and MSNBC all report similar experiences.”

Fox's 2012 situation has a parallel in something that happened in the 2010 midterms with former Fox News host and contributor John Kasich.

After leaving Congress in 2001, Kasich openly considered running for higher public office and joined Fox News to keep himself in public view. A former Kasich pollster told the Columbus Dispatch in 2002 that Kasich was “leaving himself in a position so that if something happens, he is as well-situated as somebody else.”

On March 27, 2008, the Dispatch reported that Kasich announced “he is paving the way now for a gubernatorial bid” and quoted Kasich stating: “I'm going to go forward even more aggressively, and we're going to continue to ramp it up (for a gubernatorial run).” But Fox News didn't take him off the air -- presumably because he still hadn't “officially” announced his candidacy -- and by the time he formally announced his bid on June 1, 2009, Kasich had logged more than 100 Fox News segments as a guest host or contributor.

In a column last November, Condi vs. Hillary: The Next Great Presidential Race author Dick Morris wrote that the “GOP primaries of 12 will be held on Fox News. ... we will see all the candidates on Fox News. Not just in debates, but in frequent appearances on the opinion and news shows on the network.” For once, it seems Morris is right.