Leahy said he passed on the Defense Appropriations Subcommittee so he could stay atop his current panel and thus remain a leading Senate voice on foreign policy.
When it comes to the Defense Subcommittee, Harkin is second to Leahy in seniority on the subcommittee, but a Harkin spokeswoman said Wednesday that he intends to continue as chairman of the Appropriations Subcommittee on Labor, Health and Human Services and Education.
Durbin ranks next on the seniority list. His office declined to comment on whether he would take the post.
Vice President Joe Biden waits to conduct a mock swearing-in ceremony with Sen. Brian Schatz, D-Hawaii, in the Capitol's Old Senate Chamber, December 2, 2014. Schatz was sworn in to serve the remainder of his term since he was appointed to the seat after Sen. Daniel Inouye, D-Hawaii, passed away.