"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 before 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 outshout 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 e-mails, 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 that ornaments would be distributed and participants would 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 affected them. The Bible and the Koran are also on the tree.
At 11 a.m. Sunday, the group will move to Rittenhouse Square, 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 coexistence floundered. In 2009, the Pennsylvania Pastors Network, which owned the creche, requested a location farther 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.
Contact staff writer Kathleen Brady Shea at 610-696-3815, email@example.com, or @brandywinebits on Twitter. Read her blog, "Chester County Inbox," at www.philly.com/chescoinbox.