The mysterious effort to oust NC's most powerful Republican

• Page is well-liked, well-known and has been in the public eye longer than Berger — he was first elected sheriff in 1998 — making him a formidable opponent.
• Page is reportedly considering a state Senate run but has not filed yet and did not return numerous calls inquiring about his plans. The filing deadline is Friday.

Driving the news: In the days before Thanksgiving, an unidentified group released a poll showing Page a whopping 30 points ahead of Berger in a head-to-head primary matchup.

• That's a major advantage over a long-serving incumbent, and one that's made Berger's allies question the poll's legitimacy.

Few details are known about who's behind it.

• The pollster was unnamed in a memo released on the poll, and the group that reportedly commissioned it, the North Carolina Conservative Project, does not appear to be registered with any of the government agencies it may be required to report to.
• "I generally think it's unwise to put any credence in an anonymous poll, and I certainly have not received a reception in my district that leads me to believe that that poll is in any way accurate," Berger told reporters, according to The News & Observer.

The intrigue: One person involved in the effort is political operative Patrick Sebastian, according to Berger's son, state Supreme Court Justice Phil Berger Jr.

• Sebastian was a consultant for Berger Jr. until Berger Jr. says he fired him last week following revelations that Sebastian was working to recruit someone to run against his father.
• Sebastian disputed that he was fired, saying he helped with a recent fundraiser for Berger Jr. He also said he had no formal agreement with Berger Jr. and thus there was nothing to be fired from.
• An additional wrinkle to the plot: Sebastian is the nephew of former Gov. Pat McCrory.

What they're saying: "In my conversation with Patrick [Sebastian], he confirmed that he was involved in the effort, that he should have told me weeks ago, and that he was working under a confidentiality agreement," Berger Jr. said in a text, in response to questions from Axios.

• "He also said there were a number of wealthy [or powerful] people behind the effort."
• Sebastian declined to comment on his involvement, and would not say whether he was the pollster, though he's a partner in a polling firm, Opinion Diagnostics.
• "I prefer to keep my private conversations private," Sebastian told Axios.

Between the lines: It's not unusual for political donors to fly under the radar, thanks to campaign finance laws that allow them to remain anonymous in some instances.

• But the mystery of who is propping up this effort has, so far, been especially difficult to crack.
• That could be in part because Berger's adversaries don't want to unveil themselves unless they know they can succeed; otherwise they could become enemies of one of the state's most powerful figures.

The big picture: Berger's potential challenge follows his push to legalize non-tribal casinos, including one in his district, earlier this year. That move generated significant bipartisan opposition. It also held up the passage of the state budget and, by extension, the implementation of Medicaid expansion.

• Page repeatedly spoke out against bringing a casino to Rockingham County.

Meanwhile: Page is currently running for lieutenant governor. But after the state Senate poll came out last month, Page told the News & Observer he had a lot to think about.

• He also told the outlet his team had not conducted their own poll on a potential run for that seat.

In the weeds: The North Carolina Conservative Project does not appear to be registered with the North Carolina Secretary of State, where businesses must register; the IRS, where registered tax-exempt entities can be searched by name; or the North Carolina State Board of Elections, where its expenses would be reported, depending on what kind of group it is.

Editor's note: This story has been updated with an additional comment from Sebastian.