The holiday display on the lawn of the historic courthouse in West Chester is a veritable celebration of inclusiveness, what with a Santa Claus, a Christmas tree, a toy train, a creche, and a menorah.

But in the view of the Freethought Society, something is missing - again.

For the second year in a row, the Chester County commissioners have denied the group's request to add its nine-foot-tall "Tree of Knowledge," decked with nontheist book covers, to the holiday lineup.

Margaret Downey, the Freethought Society's founder, said Monday that she was disappointed, but appreciated that Terence Farrell, chairman of the commissioners, left a phone message informing her of the decision.

"Last year," she said, "we got no response at all. We had to read the papers to find out what happened. I see that [call] as a step forward - a small step."

In 2010, the county's two Republican commissioners voted to no longer allow groups of every persuasion - including atheists - to put decorations on the historic courthouse lawn. For three years prior to that, the Tree of Knowledge had been part of the festive arrangement.

Saying that last year's policy remains in place, county spokeswoman Rebecca Brain said that the "county-owned displays include a number of U.S. Supreme Court approved secular and religious displays." On the list of approved adornments: three banners saying "Season's Greetings," "Peace on Earth" and "Happy New Year."

Downey said the commissioners' decision not to reverse their 2010 decision invites discrimination.

"It's as if they're saying, 'It's OK if you don't think like them because we don't either," she said. "The powerful can out-shout the minority."

Downey said positive response to the Freethought Society's initiative has come from skeptics, humanists, agnostics and others who have felt unrepresented during the holidays, as well as those opposed to bigotry. She has gotten appreciative calls and emails, she added, from as far away as Seattle and Canada.

On Saturday, supporters will convene at 3 p.m. at the courthouse for a "celebration/rally/protest" to promote the Tree of Knowledge as a symbol of the nontheist community. Downey said ornaments will be distributed, and participants will be invited to say a few words about how much certain books - for instance, A Portable Atheist by Christopher Hitchens, Why I Am Not a Muslim by Ibn Warraq, Misquoting Jesus by Bart Ehrman - have impacted them. The Bible and the Koran are also on the tree.

On Sunday at 11 a.m., the group will move to Rittenhouse Square in Philadelphia, where the Tree of Knowledge will be decorated for display at the Ethical Humanist Society.

"The whole point of our celebration is to show that we are not going to give up or go away," Downey said. "We'll be out there in the cold voicing our love of knowledge and freedom."

Chester County's previous, less-restrictive policy followed a failed attempt early in the decade to remove a Ten Commandments plaque from the courthouse wall.

But the effort to foster peaceful co-existence floundered. In 2009, the Pennsylvania Pastors Network, which owned the creche, requested a location farther away from the Freethought Society's tree.

Such acrimony prompted Kathi Cozzone, the minority commissioner, to advocate an end to all displays. However, her GOP counterparts opted to revoke the previous policy and create a county display.