Presidential candidates of both parties have talked more openly about their religious beliefs this year than in elections past, lifting a window on some of the values that could shape their decisions in the Oval Office. But the political benefits of such candor are not always clear in a country where most Republicans and Democrats believe in separation of church and state.

Republicans have shown off their spiritual side on the hustings in part to cement their standing with evangelical Christians, a potent voting bloc in the early-voting states of Iowa and South Carolina. The Democrats, particularly Sen. Barack Obama of Illinois, have also spoken of their journeys of faith, in part to win over Protestants and Catholics who have soured on President Bush.

Scott Keeter, survey director at the Pew Research Center, says Americans want their presidential candidates to be religious -- but not necessarily too religious.