Bill Clinton will be there. So will 300 officeholders from more than 45 states. But one thing will be missing when Democrats gather in Tennessee this weekend to discuss how to appeal to moderate, independent-minded voters in 2008: the Democratic presidential field.

Not a single one of the eight presidential candidates plans to attend the Democratic Leadership Council's summer meeting, a snub that says less about the centrist DLC than it does about a nomination process that rewards candidates who pander to their parties' hardened cores while ignoring everybody else.

"They have tunnel vision," DLC founder Al From said of his fellow Democrats.

From said he has nothing against Clinton's wife, Sen. Hillary Rodham Clinton of New York, or the other seven Democratic presidential candidates. He even understands why they won't attend the DLC meeting.

But that doesn't make him worry any less about the future of his party.

"Presidents are elected in the middle and they are elected by being bigger than their party. Neither parties' activists alone can elect somebody president," From said in a telephone interview from his Washington office. "Democrats have a long history of nominating people, including people who have lost badly. The challenge for Democrats is to nominate somebody who can win the election."

From and his moderate brethren believe that process begins this weekend in Nashville at the DLC's annual "National Conversation." It is billed as a one-of-a-kind forum for the party's rising stars to help shape the ideas and ideology behind a successful 2008 election cycle. The DLC also is launching a new Web site to promote the policies of centrist Democrats, such as:

Washington Gov. Chris Gregoire's push for electronic medical records.

Kansas Gov. Kathleen Sebelius' education reforms.

Maryland Gov. Martin O'Malley's homeland security and anti-crime initiatives.

Montana Gov. Brian Schweitzer's cutting-edge energy plans.

These governors hail from different parts of the Democratic ideology spectrum, but they have one thing in common: They are in office because they appealed to voters who hold no firm allegiance to either party.

During the 2004 presidential campaign, political operatives convinced themselves that there were a dwindling few of these so-called swing voters, and that the only way to win elections was playing to "the base" — the most dedicated Republicans and Democrats. They were wrong. The political middle is as significant as ever, with voters in a mood to swing due to their frustration with both major parties.

That raises a challenge for Republican and Democratic presidential candidates: How do they win their parties' nomination without appearing hostage to the kind of base politics that turns off swing voters?

The DLC would like to help the Democratic candidates, but none are listening.

"They are looking only at the liberal activists in Iowa," From said. "Our strength is we help candidates appeal to a broad electorate. We help people get beyond interest group politics to have a sense of national purpose. Interest group politics dominate the nomination process. But ordinary people dominate the electorate."

It's standard procedure for Democratic candidates to distance themselves from the DLC during nomination fights, only to turn to the centrist group for help during the general election when moderate voters are key. Former President Clinton was an exception when he put himself on the national stage with an address to the DLC in 1991.

His wife, a leading Democratic candidate this year, attended last summer's DLC meeting. The group, vilified by liberal bloggers, is not so important to her now, but she'll undoubtedly renew her ties to the DLC if she wins the nomination.

"It's sort of like you play on one end of field to win the nomination," From said, "but if you want to win the game, you've got to play on both ends."

He said Bush's low approval ratings give Democrats a chance to build a lasting majority in the 2008 election, but only if a Democrat wins the White House and governs effectively.

"There's more to it than trying to take advantage of the fact that Bush is down," From said. "The challenge is not just to talk to interest groups but to get beyond them and have a message that connects with the general electorate."

That is not happening, not in either party. Democratic candidates are moving to the left, Republicans to the right, as they target partisan voters.

"Candidates have their own interests. I don't blame them in a sense" for blowing off the DLC meeting, From said. "They have to get the nomination, and we're not one of the interest groups parading out there in Iowa and New Hampshire."