Millions of Democratic voters nationwide have packed polling places and caucus sites to register their voices in the historic nomination battle between Senators Barack Obama and Hillary Clinton. But several hundred party VIPs are poised to decide the nominee.
With Obama and Clinton each collecting hundreds of delegates in the nearly three dozen contests held so far, it is all but impossible for either contender to secure the nomination on pledged delegates - those assigned to candidates based on their performance in a primary or caucus - alone.
So the race almost certainly hinges on superdelegates - the nearly 800 party leaders, members of Congress, and other Democratic officials who each get a vote at the Democratic National Convention. By the campaigns' estimates, roughly 450 of the superdelegates have committed to a candidate, leaving about 350 still on the sidelines.
Even those who have already committed can change their minds, making the superdelegates an especially volatile group - and subjecting them to fierce lobbying pressure from both camps.
"It couldn't be more ironic; these are two people that party reforms were meant to bring into the Democratic Party," said Julian Zelizer, a professor of history and public affairs at Princeton University. But, he said, "They might need the bosses to kind of decide which of the 'new Democrats' wins."
The prospect of a protracted fight between Obama and Clinton is alarming to many Democrats, especially with Republicans seeming to settle on Senator John McCain of Arizona as their nominee. National Democratic Party leaders are determined to avoid a brokered Democratic National Convention this summer in Denver.
But that raises a central question: What will be the tipping point that shifts momentum permanently to one contender?
A candidate needs 2,025 delegates to win the Democratic nomination. Barring a dramatic run-of-the-table by Clinton or Obama in the weeks ahead and a concession from the other, neither will reach that tally without superdelegates. And it is impossible to know what event will catalyze superdelegates to coalesce behind one or the other (if they coalesce at all): Obama pulling off a win in Ohio or Texas on March 4 or Clinton scoring commanding victories in Ohio, Texas, and Pennsylvania?
"We don't know exactly what that number is, where that point is," said Stuart Rothenberg, who publishes the Rothenberg Political Report, a newsletter. "Clearly if somebody has a significant advantage, it's going to be very hard for the superdelegates to overturn that."
From today through early June, 1,075 pledged delegates are at stake in 18 contests. Heading into yesterday's primaries, Obama led Clinton in pledged delegates by several dozen. His sweep of the Maryland, Virginia, and District of Columbia primaries gave him the overall delegate lead for the first time.
The two campaigns have distinct strategies going forward. Clinton aides believe their path to the nomination includes maintaining an edge with superdelegates. Obama is focused more on building his lead among pledged delegates, believing that when the dust settles, superdelegates will follow the will of the voters.
Howard Wolfson, Clinton's communications director, told reporters in a conference call Monday that she will be ahead in the delegate race after the March 4 votes in Texas and Ohio, big states where she holds healthy leads in polls. "We believe we will have the delegates necessary" to win, he said.
But Obama's campaign manager, David Plouffe, told reporters on a call yesterday that pledged delegates are going to play a "leading role" in determining the party's nominee and that the campaign is concentrating on expanding its advantage among them.
"If we're able to do that, mathematical reality sets in," Plouffe said. "It becomes harder and harder for that pledged delegate lead to be overturned."
Superdelegates are feeling the pressure from both camps.
"I should put a new recording on my phone - press one if you want to talk to a superdelegate, press two if you want to talk to a real Iowa farmer," said Richard Machacek, a Democratic National Committee member who grows corn and soybeans in Winthrop, Iowa.
Machacek, who supported former senator John Edwards of North Carolina and will follow his lead if he endorses, said he had "a real nice conversation with Tom" Vilsack - a former Iowa governor who is supporting Clinton. And at a recent reception at the governor's mansion in Des Moines, Governor Chet Culver "encouraged me to consider Senator Obama."
Robin Carnahan, the secretary of state in Missouri, has basically put out a "Do Not Disturb" sign. Her brother, Russ, is a House member and superdelegate from St. Louis who endorsed Obama in May. "I talk to her regularly, but she's made it clear that as the state's chief election official, she's going to remain uncommitted," he said.
Alan Solomont, a superdelegate who is Obama's New England fund-raising chief, said Obama supporters are lobbying superdelegates, but he said they are making the case for Obama on his merits, not on loyalties or political allegiances.
"If we don't ask someone to dance, somebody else will," he said. "But at the end of the day, it's not about how many people you can persuade. It's about showing them the evidence."
Twenty years ago, Thomas A. "Tad" Devine and Harold Ickes negotiated the Democratic Party's proportional method of allocating pledged delegates that has kept this race so tight. Today, they hold different views on the role of the superdelegates in the nominating process.
Devine was Michael Dukakis's director of delegate selection in 1988 when he and Ickes - who was representing the Rev. Jesse Jackson - negotiated the current formula. Devine, who is neutral, said he believes superdelegates should hold back and ensure that the nominee is the candidate who wins the most pledged delegates in the state contests.
But Ickes, who is helping Clinton's campaign and is a superdelegate from the District of Columbia, said he believes superdelegates have a larger responsibility than merely ratifying the outcome of the caucuses and primaries.
"They are there to choose the candidate who will make the strongest candidate in the general election and also be a good president," he said.
Scott Helman can be reached at email@example.com.