Most political observers will be watching the Rev. Rick Warren's Saddleback Church tomorrow evening, where Sens. John McCain and Barack Obama are scheduled to take part in a presidential forum on faith and values.

The Saddleback event is not a debate, and McCain and Obama won't appear on stage at the same time. But both men are expected to answer a number of questions about how their personal religious views might affect their time in office.

Warren's forum has attracted a lot of media attention, but there is another event taking place this weekend that involves religion and politics – one that could, in the long run, have just as much impact on American political life.

Thousands of evangelicals are expected to gather on the National Mall in Washington for a day-long rally known as "TheCall." The event has a decided emphasis on younger evangelicals, although its organizers come from the old guard of the Religious Right.

A controversial Pentecostal visionary named Lou Engle says he was inspired to organize national rallies for young people because he was told to do so by God in a dream. The first event took place in September of 2000. This weekend's gathering is an election-year climax.

Attendees shouldn't expect to be entertained. TheCall's Web site reads, "TheCall is committed to mobilizing people from all across America to gather together to petition God for His undeserved mercy for our nation in 12-hour solemn assemblies."

Continues the site, "In the midst of an 'entertainment' driven society, TheCall does not seek to entertain, but to encounter God. Unlike other mass gatherings which attract people through the rhythms of loud music, the glamour of flashing lights, or through the appeal of charismatic personalities, TheCall is a gathering centered around the affections of a loving God. There will be no advertised bands and no promoted speakers, as our purpose is not to promote any man or ministry. The Call is a FAST not a festival. TheCall is a SOLEMN ASSEMBLY not a conference.... We believe the hour is late and the times are urgent. Our nation is in desperate need of revival and it will be only through the corporate body of Christ uniting in the place of prayer that we will find any hope in this hour. We believe we can see our nation changed as the Lord pours out His Spirit and brings refreshing to the broken, destitute, and the weary across our land."

This language appears to be a slap at the rising tide of evangelical quasi-celebrities like Warren and Joel Osteen, pastors who attract young crowds with music, fancy mega-churches and "feel-good" sermons.

That's not what Engle and his backers are about. They represent the unreconstructed, old-time Religious Right. They aren't interested in watering down the divisive social issues that have been stock and trade to this movement for so many years. Nor are they willing to add issues like opposition to global warming and care for the poor to their plate.

Engle, a 49-year-old pastor in Pasadena, Calif., holds the view that America is a battleground between God and Satan.

"I believe that there are spiritual powers contending for the soul of our nation and that all the false ideologies that affect our nation spring from the powers of darkness," he told Charisma magazine in 2001.

Engle claims prayers by his young followers led the Supreme Court to put George W. Bush in office.

"We have entered a season of time in a massive [spiritual] war," he says. "It's Pearl Harbor. It's Nazirites or Nazism. We are in a war, and if we don't win, we lose everything."

Eleven days after the Sept. 11, 2001 terrorist attacks, Engle organized a march of 50,000 people in Boston that attacked "witchcraft" and the ideas of the 18th century European Enlightenment.

More recently, Engle told The Hill newspaper in Washington that his goal is to "drive the issue of abortion like a wedge into the soul of the nation."

TheCall has been endorsed by Tony Perkins, president of the Family Research Council (FRC), and former GOP presidential candidate Mike Huckabee is scheduled to attend. The presence of these old-school types means the event is likely to have a hard edge, calling a new generation of activists to rally around issues like opposition to abortion and gay rights and support for a government under fundamentalist Christian control. Don't expect to hear a lot of talk about endangered polar bears and melting ice caps here.

Why the emphasis on the younger crowd? Clearly, something is afoot with the new generation of evangelicals. Today, both of Washington's daily newspapers, The Washington Post and The Washington Times, ran front-page stories about younger evangelicals drifting away from the Republican Party. Some are attracted to the campaign of Obama and are willing to overlook his pro-choice views on abortion.

The Religious Right's old guard is obviously worried. Evangelicals have been a reliable GOP voting bloc for years, and a drift of even a modest percentage of them away from that party could upset long-established political norms.

The situation remains fluid, but one thing is for sure: The Religious Right's old guard isn't likely to go down without a fight. They will mobilize their side and do all they can to remain politically powerful. This weekend's 12 hours of fasting and prayer is probably just the opening salvo. Another will be heard next month when thousands are expected to gather for FRC's annual "Values Voter Summit" in Washington.

You can expect to hear a lot more out of the Religious Right between now and Nov. 4.