Hilly gets dirty with Obama.

[CmdrWilkens]

'68 was also the last year of, for the Democrats, non-binding primaries. Prior to that delegates would be selected for the naitonal convention but they owed no actual loyalty to anyone. Thus whoever was actually running the convention woudl be able to, short of enourmous public pressure otherwise, get his man nominated. Thus prior to 1968 the Party Chairman or the sitting President (if he happened to be of the paticualr party) wielded enourmous power in potentially refusing to seat delegates or otherwise pushing them to support a favored candidate in return for an increased role within the party organization.

So anyway once the states began adopting presidential primaries in order to select delegates it became imperative for candidates to have support from more than just the party organization.