Bill O’Reilly of Fox News has stayed on the offensive this week after heated arguments with conservative contributor George Will. (Jeff Christensen/AP)

Bill O’Reilly just can’t let his feud with George Will rest.

Continuing the multimedia smackdown that broke out last week, the combative news host on Wednesday said detractors of his new book about former president Ronald Reagan are “jealous” of its success and that The Washington Post was being unfair in declining to publish a column he wrote defending the book against Will’s criticism.

O’Reilly’s comments came during the closing moments of his Fox News Channel program, “The O’Reilly Factor,” which was the venue for a heated exchange last Friday between O’Reilly and Will over “Killing Reagan,” the book O’Reilly co-wrote about the aftermath of the assassination attempt on the president in 1981.

The ill will between the two men was sparked last Thursday when Will excoriated O’Reilly and his book in a Post column headlined “Bill O’Reilly slanders Ronald Reagan.”

Will charged that O’Reilly and his co-author, Martin Dugard, can’t support their contention that Reagan was so impaired by John Hinckley Jr.’s attempt on his life that it affected his ability to serve as president for the next eight years. Will called the book “a tissue of unsubstantiated assertions,” a view endorsed by a number of Reagan scholars.

O’Reilly begged to differ, and the Bill-Will battle was on.

While the dispute is ostensibly about the facts of Reagan’s legacy, it also appears highly personal. O’Reilly called Will “a hack” and “a liar” during their TV interview last Friday, and complained that Will hadn’t paid him the courtesy of informing him in advance that Will’s column would be critical of the book.

Will retorted with a second O’Reilly column in The Post on Tuesday (“Bill O’Reilly makes a mess of history”). It began, “Were the lungs the seat of wisdom, Fox News host Bill O’Reilly would be wise, but they are not and he is not.”

What makes all this unusual is not just the personalities involved, but how Will and O’Reilly have a common employer, Fox News. Will is a pundit on Fox programs; O’Reilly’s eponymous program is the most popular in cable news.

The beef seems unlikely to dent O’Reilly’s book sales or his stature at Fox, where he is the network’s chief attraction.

In conversations this week, Fox executives made it clear where their loyalties lie. They said Will is one of many contributors to the network and doesn’t enjoy the same status as O’Reilly. They said O’Reilly had the full backing of Roger Ailes, Fox News’ chairman. Ailes apparently hasn’t intervened in the dispute.

Fox stood by O’Reilly earlier this year when he faced a barrage of allegations that he had distorted or exaggerated some of his reporting experiences decades ago. O’Reilly denied that he inflated the danger surrounding his exploits, much as former ‘NBC Nightly News’ anchor Brian Williams had done. Fox kept O’Reilly on the air, and the controversy drove up his ratings.

Internecine spats have occasionally broken out among the network’s opinionated personalities, such as Megyn Kelly’s shouting match (“Don’t make me cut your mic!”) with Fox News contributor Kirsten Powers in 2010, or O’Reilly’s irregular run-ins with Fox correspondent Geraldo Rivera.

But this clash pits O’Reilly against a formidable and highly respected figure: Will is a Pulitzer Prize-winning columnist who has been among the most revered conservative voices in America for the past 40 years.

O’Reilly didn’t mention Will by name in responding to viewer comments yesterday, but it was clear he was referring to the columnist when he said detractors are “jealous” of the book’s sales. “Killing Reagan” was the top title on last Sunday’s New York Times’ nonfiction bestseller list and will occupy the top spot again this Sunday.

O’Reilly and his publisher, Henry Holt & Co., asked The Post on Tuesday to publish a rebuttal to Will’s two columns, but they were rejected.

“We made it clear to his publisher that we welcomed a letter and that we would work with him to get a letter published, and that still stands,” said Fred Hiatt, The Post’s editorial editor.

The Post gets many requests to publish columns rebutting unfavorable reviews or opinions but generally doesn’t accept them on its Op-Ed page, where space is limited.

On his program last night, O’Reilly said of the decision, “The Washington Post [is] obviously not being very fair about this.”

O’Reilly and Dugard posted the rejected column on BillO’Reilly.com, his official Web site. The column also doesn’t mention Will by name but says “the hostile criticism” contained in two Post columns “is both misguided and disingenuous and is motivated by a small group of Reagan loyalists who are vehemently opposed to any objective look at the 40th President.”

Neither Will nor O’Reilly responded to requests for interviews.