Scott Lilly, the longtime Democratic staff director for the House Appropriations Committee, announced last week that he will retire at the end of the month after more than 30 years as a Congressional aide.

He will be replaced by Rob Nabors, currently the minority clerk for the Appropriations subcommittee on Commerce, Justice, State and the judiciary.

The 57-year-old Lilly has served as the top Democratic aide on the panel since 1994, when then-Chairman David Obey (D-Wis.) offered him the position of committee clerk and staff director.

“I can’t do it forever. At some point the amount of work you have to do … exceeds the energy level of a person your age,” said Lilly. “I’d rather leave before it does happen.”

Lilly, who first joined Obey’s staff in 1973, said he’d originally planned to depart last summer, but delayed his exit because “it would have been irresponsible to hand over the kind of mess we were in to someone else midstream.”

By “mess,” Lilly meant the battle over the fiscal 2004 spending bills. Congress is mandated to pass the 13 measures by Oct. 1, the start of the fiscal year, but only three were completed by that date and Congress passed an omnibus for the final seven bills in January.

Despite the ongoing spending battles and ever-increasing partisan rancor, Lilly said the Appropriations Committee has managed to remain above the fray — to a degree — due in part to the nature of its work.

His legendary personal and professional relationship with GOP Staff Director Jim Dyer — the two have served as counterparts for all of Lilly’s tenure running the shop — has been another source of stability for the panel.

“Scott Lilly and Jim Dyer have committed the horrible sin of believing that political opponents don’t have to be political enemies,” Obey said.

“I feel like Barnum when Bailey retired,” said Dyer. “Scott’s a personal friend. … We could always make this thing work.”

After nearly a decade with Lilly at the helm, some Democrats said his departure will require a period of adjustment.

“It will take time for his shoes to be filled. [Nabor is] younger. … It’ll take a while before he comes up to Scott’s stature,” said committee member Rep. John Murtha (D-Pa.).

Lilly, an Army veteran, has also served as executive director of both the Joint Economic Committee and the Democratic Study Group.

Looking to the future, Lilly plans to continue teaching a class on Congress and the executive branch at Georgetown University’s Public Policy Institute. He’s also said to be talking to John Podesta about the possibility of joining the Center for American Progress, where he would once again work alongside David Sirota, a former Democratic spokesman for House Appropriations. While Lilly said he would “like to go to some kind of think tank,” he might eventually write a book on the history of the House of Representatives, covering the 1950s and 1960s.

While Lilly will enjoy finally having the time to return to his guitar lessons — he and Obey play in the bluegrass band The Capitol Offenses — he did concede to having had a few second thoughts.

“I look at myself in the mirror each day and say, ‘Do you really want to do this?’”