Her choice, not theirs, according to a source who spoke to RCP.

After a three-year run as a paid contributor to the nation’s highest-rated cable news channel, Sarah Palin and FOX News have cut ties, according to a source close to the former Alaska governor.

“It’s my understanding that Gov. Palin was offered a contract by FOX, and she decided not to renew the arrangement,” the source close to Palin told RCP. “She remains focused on broadening her message of common-sense conservatism across the country and will be expanding her voice in the national discussion.”

The source declined to say whether Palin would pursue a television contract with another news network, such as CNN.

Not surprising given what happened last year at the convention, although the Times claims she and Fox were negotiating a new contract as recently as last week. Maybe she has another offer on the table that’s sweeter than theirs?

My first thought when I read the RCP piece was that Mark Begich is up for reelection next year and is already preparing for a strong conservative challenge, but NRO’s Robert Costa tweets some skepticism:

About Sarah Palin leaving Fox News: After spending day talking w/ Alaskans, I doubt she's running for anything. Hear she lives mostly in AZ

— Robert Costa (@costareports) January 25, 2013

I thought challenging Begich, a weak blue incumbent in a very red state, was her best bet back to political office, but maybe she’s transitioned to Arizona now. (Costa hears that she’s still occasionally in touch with Joe Miller, who appears to be planning to challenge Begich himself.) If not politics, then what? Hard to believe she’d trade Fox for CNN. Maybe … Glenn Beck’s network, The Blaze? It had 300,000 online subscribers as of last summer and must have many more now, especially since Dish Network started airing it in September. And Beck’s aggressively trying to promote it, from making a bid on Current TV to gain a platform on basic cable to opening foreign bureaus in hopes of becoming a sort of libertarian alternative to Fox. She’d instantly raise the network’s profile and bring in new viewers. And there’s plenty of room on the programming schedule for her: The channel currently airs from 9 a.m. to 8 p.m. ET with a two-hour block free from 2-4 so they could give her her own show if that’s what she has in mind. If I had to bet, I’d bet that’s where she goes.