Last month, the British Humanist Association caused a ruckus announcing a similar campaign on London buses with the message: "There's probably no God. Now stop worrying and enjoy your life."
In Washington, the humanists' campaign comes as conservative Christian groups gear up their efforts to keep Christ in Christmas. In the past five years, groups such as the American Family Association and the Catholic League have criticized or threatened boycotts of retailers who use generic "holiday" greetings.
In mid-October, the American Family Association started selling buttons that say "It's OK to say Merry Christmas."
The humanists' entry into the marketplace of ideas did not impress AFA president Tim Wildmon. "It's a stupid ad," he said. "How do we define 'good' if we don't believe in God? God in his word, the Bible, tells us what's good and bad and right and wrong. If we are each ourselves defining what's good, it's going to be a crazy world."
Also on Tuesday, the Orlando, Fla.-based Liberty Counsel, a conservative Christian legal group, launched its sixth annual "Friend or Foe Christmas Campaign." Liberty Counsel has intervened in disputes over nativity scenes and government bans on Christmas decorations, among other things.
"It's the ultimate grinch to say there is no God at a time when millions of people around the world celebrate the birth of Christ," said Mathew Staver, the group's chairman and dean of the Liberty University School of Law. "Certainly, they have the right to believe what they want but this is insulting."
Best-selling books by authors such as Richard Dawkins and Christopher Hitchens have fueled interest in "the new atheism" — a more in-your-face argument against God's existence.
Yet few Americans describe themselves as atheist or agnostic; a Pew Forum on Religion and Public Life poll from earlier this year found 92 percent of Americans believe in God.
There was no debate at the Washington Metropolitan Area Transit Authority over whether to take the ad. Spokeswoman Lisa Farbstein said the agency accepts ads that aren't obscene or pornographic.
Meanwhile, we now know that the Star of Bethlehem did mark a unique celestial event that coincided with the visit of Magi from the East to Israel. That coincidence couldn't have been by chance, given Kepler's Laws. The mysterious conjuction of Jupiter ("the king planet") and Regulus ("the king star") could only have happened because God set the celestial clock from before time.