The December 5 issue of The Economist has an enlightening piece on Donald Trump's popularity. It quotes one Trump supporter as saying "As a Christian there's lots of things I can't say. Lots of things, like 'Merry Christmas.'"

This person sees herself as a victim of the so-called "War on Christmas." She is not alone. Her perception is only partly accurate and misidentifies the most serious face of the problem.

The "War on Christmas" is a struggle over three different notions of what is to be celebrated at the end of December.

In no particular order, the first conception is that this is the Holiday Season. That even is the first line of Andy Williams's annoying tune played darn near ubiquitously this time of the year. Christmas is only one of several holidays, others being Hanukah, Kwanzaa, and New Year's Eve and Day. The appropriate greeting is the inclusive and vague "Happy Holidays" (always the plural).

The second conception is secular Christmas. This is characterized by the traditional collection of customs and practices uncoupled from their religious roots: Gift-giving, with or without Santa; Christmas trees and other seasonal household decorations; feasts with family; parties with copious drinking (including the perhaps apocryphal office parties with their legendary sexual liaisons); and mistletoe (or at least references to it) for the more amorously reserved.

Santa Claus is important for secular Christmas but only when radically disconnected from the person of St. Nicholas; Santa, the jolly giver of gifts and resident of the North Pole, has magical qualities but no spiritual content. Secular Christmas has its canon of iconic films and television specials (Holiday Inn, White Christmas, A Christmas Story, Christmas Vacation, How the Grinch Stole Christmas, A Charlie Brown Christmas, Miracle on 34th Street) and songs ("White Christmas," "Santa Claus is Coming to Town," "Silver Bells," and "The Christmas Song"). The ballet The Nutcracker is a manifestation of secular Christmas. The primary virtue of secular Christmas is merriment and the appropriate greeting therefore is "Merry Christmas."

Secular Christmas can be construed so broadly that it loses all connection to Christmas and becomes instead a celebration of winter.

The third conception is sacred Christmas. Christmas recalls and celebrates the birth of Jesus, the Messiah, the Light of the World. Its core is worship, primarily in community with fellow Christians: Christmas services at church. Its most fundamental symbol is the crèche or nativity set, with the infant in the manger, surrounded by Mary and Joseph, shepherds and angels and magi. Trees, stars, lights and Santa are honored too, but with remembrance of their original connection to the story of the Nativity.

It is the subject of few films, The Nativity Story (2006) being the sole instance that comes to mind. Arguably, though, one should count the films that pivot on divine intervention in human affairs and are set at Christmas time. It's A Wonderful Life is the most prominent example. Others are more obscure: the made for TV films The Greatest Christmas Pageant Ever and The Juggler of Notre Dame would be examples. Sacred Christmas penetrates popular culture primarily through music. Traditional carols and hymns are part of the canon of Western culture. So too are works of classical music, such as Bach's Jesu and Handel's Messiah.

Christians celebrate sacred Christmas because it is a stage in the story of salvation. Its distinctive virtues are joy and peace. Its appropriate greeting would be "Blessed Christmas" or "Joyous Christmas."

Christians should not be offended about wishing "Happy Holidays" to others, especially if they know that the others do not recognized sacred Christmas. To do so reflects a charitable impulse. The danger is that secular Christmas increasingly dominates sacred Christmas, even among Christians, and concerns not how we related to others, but to how we relate to Christmas itself.