With all the spin coming out of the GOP about the D.C. Circuit having a lower caseload than during the Bush years – and thus not needing to have its vacancies filled – it's worth remembering what was said last month by someone who knows about these things. At a September 10 Senate subcommittee hearing , Tenth Circuit Judge Timothy Tymkovich – the chair of the Judicial Conference's Committee on Judicial Resources – responded to a question about the D.C. Circuit from Sen. Christopher Coons. Judge Tymkovich (who was put on the Tenth Circuit by George W. Bush) noted that the D.C. Circuit's caseload has, in fact, not fallen during the past decade:
I might add they haven't asked for a new judgeship in the last 20-plus years or so. They lost one to transfer [in 2008]. And their caseload has been relatively steady the past ten years or so, so we haven't seen any reason to reevaluate that because their caseload is about where it was ten years ago.
(He begins discussing the D.C. Circuit at about 1:35:00 into the hearing video .)
The Judicial Conference  is an arm of the federal courts presided over by Chief Justice John Roberts and charged with setting policy on the administration of the federal courts. It regularly conducts exhaustive, in-depth analyses of the cases going through every single one of the nation's courts. On the issue of caseload, they generally know what they're talking about.