By a delicious stroke of irony, Walt Disney Pictures' new film, Narnia, opened the same week that fundamentalists were fulminating against the White House for sending out cards inscribed with best wishes for the “holiday season.”

A White House spokesman replied, reasonably enough, that since the President and Mrs. Bush send cards to both Christians and non-Christians at this time of year, they chose to use a non-sectarian greeting.

But the fundamentalists are on a crusade to “Keep Christ in Christmas.” When I heard about their attacks on the White House “holiday” card, I wondered, “What kind of cards do those people send to their own Jewish friends at this time of year … or don’t they have any?” And, besides, what does the picture that adorns the front of this year's card -- two terriers and a cat frolicking on a snowy White House lawn -- have to do with Christmas?

Narnia, I suppose, offered the fundamentalists some consolation, since the movie is based on C.S. Lewis’ beloved classic, The Lion, the Witch and the Wardrobe. Lewis (1898-1963) was one of the greatest Christian apologists of the 20th Century, and his Narnia stories have a profound Christian subtext.

But Lewis, who had a rich sense of humor, also had something to say about the practice of sending cards at this time of year. In a wickedly funny essay, “Exmas and Chrissmas,” which purports to be a missing chapter from Herodotus, Lewis describes the winter customs of the people of Niatirb (Britain spelled backwards).

Among these customs is the following:

“Every citizen is obliged to send to each of his friends a square piece of hard paper stamped with a picture, which in their speech is called an Exmas-card. But the pictures represent birds sitting on branches, or trees with a dark green prickly leaf, or else men in such garments as the Niatirbians believe that their ancestors wore two hundred years ago riding in coaches such as their ancestors used, or houses with snow on their roofs. And the Niatirbians are unwilling to say what these pictures have to do with the festival; guarding (as I suppose) some sacred mystery. And because all men must send these cards the marketplace is filled with the crowd of those buying them, so that there is great labour and weariness.

“But having bought as many as they suppose to be sufficient, they return to their houses and find there the like cards which others have sent to them. And when they find cards from any to whom they also have sent cards, they throw them away and give thanks to the gods that this labour at least is over for another year. But when they find cards from any to whom they have not sent, then they beat their breasts and wail and utter curses against the sender; and, having sufficiently lamented their misfortune, they put on their boots again and go out in the fog and rain to buy a card for him also.”

From Exmas cards, “Herodotus” goes on to discuss the custom of exchanging costly Exmas gifts -- gifts, very often, that the givers cannot afford and that the recipients don't need. When he asks a priest at one of the temples why the Niatirbians put up with the stress and expense of the Exmas Rush, the priest informs him, “It is, O Stranger, a racket.”

“Herodotus” then explains that Exmas is the principal winter holiday of the Niatirbians, since it is kept by the great majority of the people. But there is also a smaller festival, called Chrissmas, that is kept by very few:

“And those who keep Chrissmas, doing the opposite of the majority of the Niatirbians, rise early on that day and go before sunrise to certain temples where they partake of a sacred feast. And in most of the temples they set out images of a fair woman with a new-born Child on her knees and certain animals and shepherds adoring the Child. (The reason of these images is giving in a certain sacred story which I know but do not repeat.)”

Lewis wrote this essay some fifty years ago, and the slogan “Keep Christ in Christmas” has been around for about the same length of time. But the slogan has not stopped some of the nation’s megachurches from canceling their services because Christmas falls on a Sunday this year.

Irony upon irony.

It seems to me that if certain Christians really want to “Keep Christ in Christmas,” they should not start by protesting the White House's choice of holiday greeting. Nor should they start by demanding that their local department stores wish their Jewish customers a Merry Christmas. They ought to start by picketing the churches that are going to close on a Sunday so that their worldly congregations can celebrate what Lewis called “Exmas.” That is a real sacrilege.