Religious themes have been more likely to take center stage at recent Republican National Conventions than at Democratic gatherings. But politics and religion will be mingling all this week when Democrats convene in Denver to choose Barack Obama as their presidential nominee.

Spurred by a presidential candidate who freely talks about his religious beliefs, Democrats will go to great lengths to display their own religious fervor. Obama's selection of Joe Biden as his running mate probably enhances the theme. Biden made a point of talking about his Irish-Catholic roots in Saturday's joint appearance with Obama.

For the first time ever, Democrats have planned "faith caucus meetings" led by an array of religious and spiritual leaders, including Christians, Muslims and Jews. Democrats want to convince voters that they are putting their faith in action — and show that Republicans haven't cornered the market on family values or faith.

"Everybody woke up after the last election and realized the Democratic Party had not done well dealing with religious voters," says Steven Waldman, founder of the online spiritual center beliefnet.com.

Democrats have occasionally struggled to adopt religious themes when they gathered every four years. Part of the reason may be that a mix of Protestants, Catholics, Jews and non-believers were trying to co-exist under one roof. They found the best way to do that was to move religion to the side. The GOP, by contrast, was — until relatively recently — predominantly Protestant.

"Republicans were able to use religion more effectively," says Jim Wallis, founder of faith-based Sojourners magazine.

Barack Obama hopes to overturn that perception, says Wallis, who will be leading faith caucus meetings at the convention. Evangelical voters could be essential to a presidential victory — by either candidate — in November.

The agenda of the religious community has changed, Wallis says. As recently as two years ago, many religious Americans were focused only on issues such as gay marriage and abortion.

The new generation of religious citizens "has a wider, deeper agenda that includes poverty, protecting the environment or 'creation care', war and peace, human trafficking and Darfur, for instance," he says.

This convention will try to juggle all of these concerns. "I believe in separation of church and state, and so does Barack Obama," says Wallis. "But that doesn't mean segregation of moral values from public life or the banishing of religious language from the public square. Dr. [Martin Luther] King invoked the prophets Jeremiah, Isaiah and Jesus. He spoke with a Bible in one hand and the constitution in the other."