Priscilla L. Southwell, "A backroom without the smoke? Superdelegates and the 2008 Democratic nomination process," Party Politics, 18 (March, 2012): 267-283. [Available at http://ppq.sagepub.com/content/vol18/issue2/ ]

First paragraph:
In the desire to give party leaders and elected officials a more important role in the nomination process, the Democratic Party, under the auspices of the 1982 Hunt Commission, allocated additional slots to the states for the inclusion of governors, large-city mayors, members of Congress and state party chairs as unpledged delegates to its national convention. The bloc of party leaders and elected officials, or 'superdelegates', thus dramatically increased from 8 percent of the total delegates at the 1980 convention to 15.5 percent in 1984 (Report of the Commission on Presidential Nomination, 26 March 1982, hereafter referred to as the Hunt Commission Report) and has continued to rise in subsequent elections. Superdelegates made up approximately 20 percent of the convention delegates at the 2008 convention.

Figures and Tables:

Table 1. 2008 superdelegate endorsements by gendera and raceb

Table 2. 2008 superdelegate endorsements by typea

Table 3. 2008 superdelegate endorsements by type and state winnera

Table 4. Candidate contributions to 2008 superdelegates by type: 2005-6 and 2007-8 election cycles [mean contribution (n)]

Table 5. Binary logit analysis of candidate endorsement by 2008 Democratic superdelegatesa

Table 6. Delegate allocation by states, Democratic 2008 nomination process Table 7. Hypothetical estimates of 2008 delegate tallya

Last Paragraph:
The Democratic Party might wish to head off such controversy before it occurs again. First, it would seem a good public relations step to discourage presidential candidates from making campaign contributions to any convention delegates once they have achieved delegate status. Second, the party could reduce substantially the number of party leaders and elected officials at the convention, from 20 percent to 8-10 percent, as was the case before 1984. Alternatively, the party can require that the bulk of superdelegates be pledged, or that superdelegate endorsements be delayed, until the end of the campaign season. The party may have to adjust its rules, once again, to maintain an acceptable balance of power between elite and rank-and-file members.