They are known as superdelegates, and the two Democratic presidential candidates are recruiting them to form an army of superheroes ready to swoop in at the hour of peril.
According to the Democratic Party's complex nomination system, a hefty 20 percent of all delegates - 796 to be exact - are not in any way obligated to reflect the will of the voters. Instead, these prominent elected officials and other party activists have the power to vote as they please.
In this year's remarkably competitive race between Hillary Clinton and Barack Obama, the superdelegates could end up deciding who gets the nomination. Well aware of that, the two candidates have been courting them assiduously.
"It's hot and heavy," said Elaine Kamarck, a superdelegate who teaches at Harvard University's Kennedy School of Government. "They call you, they send you things, they invite you to things. They have people who know you call you."
Kamarck endorsed Clinton in August, but the Obama people didn't give up calling her for a while. The Clinton campaign has also asked Kamarck, who was senior policy adviser to Al Gore during his 2000 presidential campaign, to call other former Gore supporters.
At the moment, superdelegates give the edge to Clinton, staking her to an overall lead in delegates though Obama has won more delegates in primaries and caucuses. An Associated Press survey in December found that the vast majority of superdelegates were undecided, but Clinton had support from 169, compared with 63 for Obama and 34 for John Edwards, who bowed out of the race Wednesday. A candidate needs 2,025 delegates to secure the Democratic nomination.
Some political observers believe that the Clinton campaign more aggressively sought the support of superdelegates earlier in the race, but that most of the New York senator's advantage reflects the fact that she had more relationships with other Democrats going back to her husband's presidency and that she was seen as the front-runner for much of last year.
Superdelegates include all Democratic members of Congress, Democratic governors, members of the Democratic National Committee, mayors, and other "party leaders" such as former presidents and former congressional leaders, and onetime top DNC officials.
On the Republican side, where 1,191 delegates are needed for the nomination, 463 "unbound" delegates who are elected officials and other party leaders are, like the superdelegates, free to choose whom to vote for.
Many superdelegates are sought after primarily for their public support and the cachet it brings, such as Senator Edward M. Kennedy's endorsement this week of Obama or US Representative Maxine Waters's endorsement of Clinton. But lesser-known officials may be just as valuable if no candidate wins enough delegates and there is a brokered Democratic convention in Denver in August.
Many of Obama's high-profile endorsements by superdelegates came only after his wins in Iowa and then South Carolina, and his campaign hopes that they will continue to fall for him like dominoes. Obama supporters believe that Kennedy, a towering figure for party faithful, reassures other superdelegates that the candidate can do well among traditional Democrats, while the backing of a leader in a heavily Republican state, such as Governor Kathleen Sebelius of Kansas, makes the case that Obama can win over independents and even Republicans.
Because many superdelegates have to run for reelection themselves in November and may be personally affected by the name on the top of the ticket, electability in the general election "might be more on the mind of a superdelegate" than that of an ordinary voter, said Alan Solomont, a Massachusetts superdelegate and a major fund-raiser for Obama.
However, many superdelegates - the majority so far - have been unwilling to commit when the outcome of the race is so uncertain. Traditionally, they coalesce around the front-runner in an effort to build party unity.
"Loyalty is an important factor in this business, for some people the most important factor," said Steve Grossman, a top Clinton fund-raiser and a Massachusetts superdelegate. "But you also have a lot of people who want to be with the winner."
And it's important to remember that even those who have committed can change their mind.
If Clinton and Obama end up nearly tied when they reach the convention and the superdelegates do, in fact, end up with the power to decide the party's nominee, superdelegates would probably face pressure to go with the candidate who is ahead among the delegates chosen through primaries and caucuses.
Otherwise, they could be accused of robbing the voters of their say or anointing a candidate who would go into the general election with less popular support.
"There would be a lot of pressure to go with the will of the majority," Grossman said.
Marcella Bombardieri can be reached at firstname.lastname@example.org.