The conventional wisdom in American politics has long been that someone who is not religious cannot be elected president of the United States. Most Americans have consistently said that it is important to them that the president have strong religious beliefs. And a new Pew Research Center survey finds that being an atheist remains one of the biggest liabilities that a presidential candidate can have; fully half of American adults say they would be less likely to vote for a hypothetical presidential candidate who does not believe in God, while just 6% say they would be more likely to vote for a nonbeliever. On the other hand, the share of American adults who say they would be less likely to vote for an atheist candidate has been declining over time. Moreover, one of the candidates who is widely viewed by Republicans as a potentially "good" or "great" president, Donald Trump, is not widely viewed as a religious person, even by those in his own party. And on the Democratic side, the share of Americans who say Hillary Clinton is not a religious person now stands at 43%, which is sharply higher than it was in the summer of 2007, when she was seeking the presidential nomination for the first time. These are among the key findings of a new Pew Research Center survey conducted Jan. 7-14, 2016, on landlines and cellphones among a national sample of 2,009 adults. This is the latest in a long line of research the Center has conducted on the role of religion in presidential campaigns.