Though the first caucuses and primaries are still weeks away, Hillary Clinton already has a significant lead in the race for the Democratic Party's nomination.

According to a survey conducted by the Associated Press in November, in which more than 80 percent of the party's 712 superdelegates stated which candidate they plan to support at the convention in Philadelphia, 359 said they would be supporting Clinton, compared to just 8 for Bernie Sanders and 2 for Martin O'Malley (210 said they were "uncommitted").

With more than half of the superdelegates already intending to vote for her, Clinton is beginning the contest with a 15 percent head start in the effort to win the 2,382 delegates needed to have majority support at the July convention -- and not a single primary vote has been cast yet.

Clinton's overwhelming support from superdelegates reflects her standing among the party's establishment. More than half of the superdelegates consist of the elected membership of the party's national organization, the Democratic National Committee (DNC). The other superdelegates include Democratic governors, Democratic members of the House and the Senate (voting and non-voting), and other "distinguished party leaders," including current and former presidents, vice presidents, and DNC chairs.

Superdelegates' preferences vary from state to state. In Washington, which has 17 superdelegates, the governor and all of the state's congresspersons have expressed their support for Clinton, but the state members of the DNC have announced their intention to await the state's caucus results before pledging to support a particular candidate.

Pennsylvania, there is broader support for Clinton. Having contacted 17 of the state's 21 superdelegates, the AP found that 14 of them supported Clinton, including the chairman of the state Democratic Party. Three superdelegates stated they were uncommitted, including Rep. Brendan Boyle, who cited his sympathy with Sanders' concern for income inequality and his friendship with O'Malley.

Clinton's popularity among superdelegates is not coincidental: one reason for enfranchising Democratic "PLEO" (party leaders and elected officials) at nominating conventions in the 1980s was to curb the growing influence of "outsider" candidates and their supporters and to ensure that the eventual nominee had the blessing of the party's establishment.

As the New York Times summarized the rationale, superdelegates could either "provide a potential nominee, deemed worthy and electable, with a confirming boost" or "check the progress of a potential nominee leading by a narrow margin but not esteemed ."

To properly understand the origin and role of superdelegates, one must go all the way back to the chaotic Democratic National Convention held in Chicago in the summer of 1968.

There, the party leadership secured the nomination of Vice President Hubert Humphrey despite Humphrey having not competed in any of the 15 Democratic primaries (where anti-war candidates Robert Kennedy and Eugene McCarthy had won a majority of the delegates). Party leaders, including Chicago mayor Richard Daley, were credited with finagling the delegate selection process to ensure that pro-Humphrey delegates outnumbered those in favor of the "peace plank" on the convention floor.

Eager to prevent a repeat of the internal strife and ensuing riots that tarnished the Chicago convention, the party organized several commissions to reform the nominating process.

The McGovern-Fraser Commission issued a provision requiring that delegate selection should be "open," meaning that delegates would be selected by voters rather than party leaders. While this reform had the intended goal of regulating the caucus system to prevent its manipulation by party bosses, it had the unintended consequence of prompting state parties to adopt primaries instead: by 1972, the number of states where Democratic primaries occurred increased to 23.

Concerned that the trend toward primaries would weaken the power of the party organization, the Democratic Party established the Winograd Commission. Yet after the nomination and election of Jimmy Carter, the commission's attention turned to other matters. Among its final proposals was a "bound-delegate" rule – Rule 11 (H), which stipulated that delegates were obligated to support the candidate the voters had chosen (in accordance with the outcome of the caucus or primary).

Rule 11 (H) became a point of contention during the 1980 election season, when Democratic candidate Ted Kennedy tried to persuade some delegates to abandon their support for Carter and support him instead. Though Kennedy failed to secure the nomination, he did succeed in provoking a minor emendation of the party's rules.

The subsequent Hunt Commission sought to undue some of the reforms of the McGovern-Fraser Commission, which – like the proportional allocation of delegates and party machine-busting affirmative action quotas – had been proposed to empower "insurgent" candidates who lacked the backing of the party leadership.

In addition to softening the wording of Rule 11 (H) to require that delegates should, "in all good conscience reflect the sentiments of those who elected them," the commission also sought to empower Democratic officials, especially Democrats in Congress, who felt unfairly excluded from the nominating process and less inclined to campaign on behalf of the eventual nominee.

The chair of the commission, Governor James Hunt of North Carolina, proposed to "return a measure of decision-making power and discretion to the organized party" by allowing "a substantial number of party leader and elected official delegates to be selected without requiring a prior declaration of preference." The result was the creation of the "unpledged" superdelegate.

While Hunt framed the reform in terms of inclusiveness, he also declared that the commission's purpose was to formulate rules "that will help us choose a nominee who can win," an idea that today is simply expressed – most often by general election-conscious party elites – with the word "electability."

The commission initially proposed that 30 percent of the convention’s delegates should be unpledged. That figure was eventually whittled down to 14 percent by the time of the 1984 convention, which is approximately what the figure is today.

While some argue that Clinton's early lead is not insurmountable and that superdelegates may yet break for Sanders, history shows that the establishment has typically been successful at protecting their favorite candidate against outsider candidates, such as Eugene McCarthy (1968), Gary Hart (1984), and Jesse Jackson (1988).

However, early superdelegate support has not always guaranteed a candidate would receive the party's nomination. In 2008, Clinton had an early lead among superdelegates against Obama but eventually lost that majority support – and the nomination – by the time the delegates convened in August.

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