Among the red-letter dates in the history of Christianity, there is December 25, 0000, and there is that day in 1974 when It's a Wonderful Life lost its copyright protection and became a public-domain property. As a result, television stations could broadcast the film at no cost whenever they wanted-typically on or around Christmas-and so they did, copiously. It's a Wonderful Life had hardly been a box-office bruiser upon its initial release late in 1946, but now people were watching-if not because they figured it for a classic, then at least because it was Christmas and nothing else was on.

Both the director, Frank Capra, and the star, James Stewart, were delighted that their own favourite film had finally become a favourite among so many American families. They were less delighted when the movie was colourized; both thought that an abomination, and Stewart, a man of few disparaging words, actually told Congress it physically sickened him. But eventually the copyright was rescued, protecting Capra's original black-and-white beauty for the posterity that probably has it on in the living room right now. What were the chances?

Within a few years of the 1843 publication of A Christmas Carol, a proper Victorian Christmas celebration seemed to require an experience of that book. A century later, Frank Capra offered essentially the same service to a modern audience with It's a Wonderful Life.

At Christmastime in the United States, It's a Wonderful Life has become a seasonal duty, like shopping and complaining about shopping and turns indulging the in-laws. The movie could have remained an abstraction or a kitschy annoyance, like so many of our holiday festoons, but it has stayed alive, and still has real value to us. To see why, try sitting down and actually watching it this year. If you can get past the several mawkish moments, you might make a surprising discovery: it's a wonderful movie.

In many ways, Capra's film is a Dickensian achievement. Within a few years of the 1843 publication of A Christmas Carol, a proper Victorian Christmas celebration seemed to require an experience of that book. It was typically played as a kind of revelling respite from accelerated, industrialized urban life, with a nostalgic emphasis on the communal virtues (charity, kindness) eroded by that life. A century later, Frank Capra offered essentially the same service to a modern audience with It's a Wonderful Life. Each story provided a kind of divine deliverance for its protagonist-and by extension its audience-and each was the feel-good story of its century. Each can still be used by either side of the political spectrum as ammunition in the values debate. Of course, neither could be produced anew now, yet neither is about to go away any time soon.

That's because we First Worlders need to have our humility checked once in a while, and the holiday season seems as good a time as any. 'Tis the season for measuring our fortunes, financial and otherwise; having most likely spent the year debasing ourselves and each other with selfish urges, we need to give the gift of reliable redemption. That means annual reminders of Scrooge's transformation from miserly prick to very good boss and do-overs of George Bailey's arc from suicidal solipsist to tender-hearted pillar of family and community.

Well, maybe a ghost or an angel will give you a glimpse of life without It's a Wonderful Life. And what would be left but plodding parades and football games and stale sitcoms?

Bailey (Stewart, the consummate charmer), trapped in the small town in which he grew up, driven to ruin by a predatory banker (Lionel Barrymore, the consummate bastard) and wishing he'd never been born, gets to see what life would be like without him (not wonderful). As Capra said of the film's genesis, "Sometimes a greater lesson can be read into a bad example than a good one." Dickens did well with the same strategy. And although both had a positive outcome in mind, neither the writer nor the filmmaker was afraid to give voice to real despair. For every moment of hope and good cheer in these works, there is an outburst of rage and cruelty; for every whitewashed sweet spot, some brutal bitterness. The power comes from our inability to be embarrassed by Scrooge and Bailey when their epiphanies come and they go gleefully ranting through the streets, spouting Christmas spirit. They've earned it.

As with A Christmas Carol, we can watch It's A Wonderful Life at other times of year, and of course it holds up, but it does lose a little focus, like the spray of Christmas lights left up year-round: still pretty, sure, but less special.

On the other hand, you might say you'd prefer just one holiday season without yet another showing of it. Well, maybe a ghost or an angel will give you a glimpse of life without It's a Wonderful Life. And what would be left but plodding parades and football games and stale sitcoms? To paraphrase the angel Clarence, it would leave an awful hole in the holiday TV lineup, wouldn't it?

Maisonneuve contributing editor Jonathan Kiefer writes about the arts for various publications in San Francisco, where he lives. One of his cats is named after Preston Sturges. Film Flâneur appears every second Friday.