As the debate around religious freedom heats up across the country, one group has become increasingly central to the conversation: Atheists.

Earlier this month, lawmakers in Madison, Wis. voted to give atheists the same protections for employment, housing, and public accommodations as other groups – making the city the first in the nation to include atheists in its list of protected classes.

The decision, coupled with growing media attention and the rising number of atheists and religiously unaffiliated across the United States, may be a sign of shifting perceptions around those who reject religious beliefs.  

Among the least accepted groups in the United States today, atheists have long faced discrimination in politics, military service, and schools, as well as hostility in everyday life.

Eight states have laws that technically prohibit atheists from holding office: Arkansas, Maryland, Mississippi, North Carolina, Pennsylvania, South Carolina, Tennessee, and Texas. A 1961 Supreme Court ruling prevents these laws from being actively enforced, yet there are no openly atheist members of Congress, The Washington Post reported.

In 2013, news magazine The Week published a piece about the US military’s religious requirement for recruits, which classified as a potential risk indicator a “lack or loss of spiritual faith.” While advocates of the policy said it aimed to strengthen emotional well-being among troops, where suicide rates were on the rise, others saw it as discriminatory and unconstitutional, according to the report.

"This country was founded on a very critical principle – the Founding Framers looked at the horrors that occurred throughout history by mixing religion and war, and they said, ’We’re going to separate church and state,’” Mikey Weinstein, a former Air Force officer and founder and president of the Military Religious Freedom Foundation, told The Week. “And that means they cannot test for religion in the military."

Similar debates have played out in other parts of American life: at schools, during child custody battles, in advertising. For the most part, atheists and advocates of secularism have had to fight against a prevailing public perception in which they are seen in a negative light.

“Like a light switch, it’s, ‘You’re immoral, you’re gonna raise evil children, you’re a bad parent,’” Todd Stiefel, a former Catholic who now leads a nationwide campaign called Openly Secular, told CBS News. “They’re questioning your whole existence. It’s painful. It’s discrimination.”

About half of Americans surveyed in a Pew Research Center study said they would be less likely to vote for an atheist candidate for president, versus less than 40 percent who said the same about an adulterous one.

Another report found that nearly half of all Americans would be unhappy if a family member married someone who does not believe in God, while 53 percent said it is necessary to believe in God to be moral.

Overall, 40 percent of Americans viewed atheists negatively, rating them 33 or below on a scale of 1 to 100.

One study in 2011 found that a central motivation driving animosity against atheists is mistrust: “Participants found a description of an untrustworthy person to be more representative of atheists than of Christians, Muslims, gay men, feminists, or Jewish people,” the researchers wrote. “Only people with a proven track record of untrustworthy conduct – rapists – were distrusted to a comparable degree as atheists.”

“We challenge the whole concept that you can’t be good without God,” David Silverman, president of American Atheists, explained to Slate. “We challenge the idea that religion is important in the first place, and that really makes them uncomfortable.”

Things may be starting to change for atheists, however, as the new law in Madison shows.

In March, an avowed atheist spoke at the Conservative Political Action Conference (CPAC) for the first time in history, and she urged Republicans to reach out to young people who identify as secular.

“Embrace me,” Jamila Bey, an African American journalist and board member of the group American Atheists, said at the 41st annual CPAC. “Let me vote for GOP candidates.”

Part of the reason for the shift is a decline in religious affiliation in the United States: About 20 percent of the US general public considered themselves religiously unaffiliated in 2012, up from about 15 percent in 2007, according to Pew. About 7 percent of the public said they did not believe in "God or universal spirit."

It also helps that the rising number of children “growing up godless” has not resulted in moral mayhem. As Phil Zuckerman, professor of sociology and secular studies at Pitzer College in Claremont, Calif., wrote in an op-ed for the LA Times:

“It’s about changing hearts and changing minds,” Openly Secular’s Mr. Stiefel told CBS. “It’s about people realizing that we are somebody you don’t need to fear. We’re somebody you don’t need to distrust.”