Updated 10:35 p.m.

House Majority Whip James Clyburn (D-S.C.) is stressing his support for the seniority system in the battle over the gavel between Energy and Commerce Chairman John Dingell (D-Mich.) and Rep. Henry Waxman (D-Calif.), but his office says he is not explicitly endorsing the incumbent Dingell.

Along with other members of the Congressional Black Caucus, Clyburn is worried that a move to unseat Dingell would undercut the seniority system, Clyburn spokeswoman Kristie Greco told Bloomberg.

However, Greco told Roll Call that Clyburn is staying out of endorsements in leadership races. “Congressman Clyburn has not made an endorsement in this race,” Greco said.

Waxman, who launched a surprise bid for the chairmanship earlier this month, is the second-ranking Democrat on Energy and Commerce.