The ads by the Freedom From Religion Foundation take a more inviting approach, with big portraits of some famous and some workaday people, listing their hobbies and professions and giving a punchy, personal declaration of independence from religion. The group, which has been running advertisements on and off since 2007, has spent about $55,000 this year to put up 150 billboards in about a dozen cities.

One, featuring Barbara Wright, a restaurateur in Madison, says: “It’s not what you believe, but how you behave.”

Another running throughout the South shows Butterfly McQueen, the late actress who played Scarlett O’Hara’s maid in “Gone With the Wind.” The billboard says, “As my ancestors are free from slavery, I am free from the slavery of religion.”