(CNN) The chairman of the Congressional Black Caucus blasted proposed changes to Democratic "superdelegate" rules that would limit their ability to vote on the first ballot for the party's presidential nominees.

In a letter to Democratic National Committee Chairman Tom Perez dated Monday, Louisiana Rep. Cedric Richmond wrote on behalf of "many" of his colleagues in the caucus to urge him to withdraw support of the changes to be voted on at the party's meeting at the end of the month.

"There should be enough room in the process to include the perspective of local party activists and officials, and Members of Congress. One group should not be harmed at the expense of the other," Richmond wrote. "Passage of the reforms in their current form would disenfranchise elected officials for no substantive reason and would create unnecessary competition between those elected and their constituents."

The proposed plan -- known as the "third way plus" option -- does not allow superdelegates to vote at the convention for the presidential nominee on the first ballot unless a candidate has been certified to have earned a majority of the entire convention through pledged delegates only. This ensures superdelegates could not change the outcome of the nomination process on the first ballot, which detractors of the plan point out has never happened since they were created in the 1980s.

During the 2016 nomination process, superdelegates -- who made up about 15% of all delegates at the convention -- came under intense criticism by supporters of Sen. Bernie Sanders. They argued that Hillary Clinton's early superdelegate support bolstered her position during the primaries, in which she beat the Vermont senator for the Democratic nomination.

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