Locked in a race with an uncertain outcome, representatives for both camps directed the California Democratic Party this week to delete a raft of names from lists of some 2,400 potential delegates who will be elected Sunday in party caucuses.
Driven by fears that some prospective delegates might be concealing their true allegiances, campaigns have weeded out dubious candidates by searching campaign-finance data, scouring the Internet and making phone calls. Both sides want to guard against electing delegates who might actually support their rival -- or even a fringe candidate.
Most of the cutting was done by the Illinois senator -- about 900 potential Obama delegates were dropped by his campaign, with about 50 excluded on Clinton's side.
Roger Salazar, a Democratic operative running as a Clinton delegate, compared the behind-the-scenes screening to jury selection.
The campaigns "want to make sure the people who are running for delegate for their candidate are going to stay true to that candidate," Salazar said. "If they see somebody who is a supporter of the other side, they are going to knock them off" the candidate list for each congressional district.
Obama, who has been successful mobilizing grass roots voters, could face blowback from the cuts.
"It's shocking that they cut out so many young activists," said Rocky Fernandez of Hayward, president of the California Young Democrats, who was dropped from Obama's delegate ballot despite traveling to New Hampshire and Nevada to volunteer for the campaign. "A lot of these people paid out of their own pockets to volunteer in so many places."
Still, Fernandez said he remained an Obama supporter.
San Francisco blogger and political consultant Brian Leubitz traveled to Nevada and Texas to help Obama and also donated a small amount of money to the campaign, then found out he was ousted from the delegate ballot.
He earlier donated to John Edwards when the former North Carolina senator was in the race.
"I didn't think I was going to win ... but I'm kind of surprised they just dropped me," Leubitz said. "I don't think I'm going to change my allegiances, but it does increase my cynicism, which is the opposite of the campaign's mantra."
More than 4,000 delegates from across the nation will travel to Denver in August to select the Democratic presidential nominee. Slots for 241 delegates divvied up in California's Feb. 5 presidential primary -- 134 for Clinton and 107 for Obama -- will be awarded Sunday.
Some say the political intrigue -- the notion of meddlers or Trojan Horse delegates -- might be overstated.
"Most delegates are legitimate, but with this convention no one is taking any chances," said Steven Maviglio, who's running as a Clinton delegate in Sacramento and is an aide to her national co-chair Fabian Nunez, the state Assembly speaker. "At this point of the game, each campaign wants its delegates to be 100 percent committed."
The suspicions about delegates' loyalty has been heightened because there are no party rules that guarantee they must vote in Denver for the candidate to which they are pledged during elections.
The former first lady trails Obama both in the popular vote and in the pledged delegates won in primaries and caucuses, and she has said she will take her fight for the nomination to the Denver convention if necessary.
She has hinted she hopes to persuade a few of his delegates to back her instead of the Illinois senator. "There is no such thing as a pledged delegate," Clinton has said.
Although many delegate candidates are well known, there is little information on others and some have proven a mystery. The California delegate races and caucuses are open to any registered Democrat, although the candidates must declare their support for Obama or Clinton.
The campaigns submit lists of their approved delegate candidates to the party, which then become the official ballot at the caucuses. But determining who should be on those ballots is a delicate job -- the campaigns are eager to send loyalists to Denver and drop potential troublemakers, but they want to avoid inadvertently blocking rank-and-file Democrats from pursuing a trip to the convention. They must also meet demographic benchmarks to be seated in Denver.
The delegates at stake in caucuses Sunday represent only a portion of those who will attend the convention from California. Others will include 71 superdelegates, who range from members of Congress to former party leaders, and another group of 129 delegates who will be chosen next month, based on the statewide primary vote tally.
Some of delegate confusion can be blamed on timing. California's Democratic caucuses have traditionally taken place before the presidential primary. When the state moved its primary to Feb. 5 from June to become part of the Super Tuesday contests, the caucus date landed after the election.
Obama campaign spokesman Ben LaBolt declined comment. Clinton's campaign had no immediate comment.