Democratic Party bonus delegates

In another thread, I learned that the Democrats will give bonus delegates to states that have late primaries. Looking things up, I find this page:

Summary: States having their primary in April will get an additional 10% delegates and those after April, an additional 20%. Furthermore, a cluster of three or more neighboring states that have their primaries at the same time (but after March 25) will get an additional 15%. (States and territories that are not adjacent to any others have defined adjacencies.)

When did they institute these bonus rules? Are they new this year or have they been around for a while?

How do they define the clusters of neighboring states? Would Virginia, Tennessee and Arkansas constitute a cluster even though Virginia and Arkansas are not neighbors? (Maybe this hasn’t come up, so perhaps they haven’t had to decide it.)

Because allowing the most rural and non-diverse states pick the nominee by the end of January hasn’t exactly generated the best results.

Not why, but when. Are these new for this election cycle or have they been around for previous ones?

Looks like 2008.

Bonus delegates are awarded to states holding their First Determining Step (start their delegate allocation process) later in the cycle. The bonus is awarded as a percentage of the base allocation of pledged delegates and applies to the district and at-large delegates. The bonus does NOT apply to the Pledged PLEO and Unpledged delegates.

Source: Democratic Delegate Allocation - 2008

No mention of bonus delegates in the same doc from 2004 (Democratic Delegate Allocation - 2004).

Contrary to Smapti’s uninformed opinion, bonus delegates were put in place to incentivize states scheduling their primaries later which, in some sense, preserved the system where a few non-diverse, rural states had disproportionate weight.

Thanks @Lance_Turbo.

As long as you can get from any state in the cluster to any other state by going only through states in the cluster, it counts. I don’t see any clusters on the 2024 planned schedule. I think there was one in 2020; DC, Maryland, and Pennsylvania were all on June 2, despite the fact that DC does not touch Pennsylvania.

Thanks, @That_Don_Guy.