Former Patton Boggs managing partner Stuart Pape is leaving, one of several who have left the lobbying firm after its absorption by Squire Sanders last year. (Jeffrey MacMillan/Capital Business)

Stuart Pape, the former managing partner of Washington lobbying powerhouse Patton Boggs, is leaving the firm to join law firm Polsinelli.

Pape was managing partner under Patton Boggs chairman Tommy Boggs, Jr., from 1996 to 2010, and is regarded by many Patton partners as a popular leader. His departure marks a changing of the guard at the firm. Since Patton was absorbed by the larger law firm Squire Sanders last year, a number of longtime Patton attorneys have left to join other firms, including high-profile partners such as Robert Luskin, who announced in January that he will be joining Paul Hastings. Pape did not have a leadership role in the merged firm, Squire Patton Boggs.

News of Pape’s move was reported earlier Wednesday by the National Law Journal.

Pape, a Food and Drug Administration attorney, is slated to start at Polsinelli on Thursday, and will bring a partner, Carey Nuttall, and of counsel Anne Spiggle with him. He is to lead Polsinelli’s FDA group. Polsinelli has 19 U.S. offices and 740 attorneys, including about 40 in Washington.

“It’s a mixture of excitement about the future and sadness about leaving so much of my professional life behind,” said Pape, who spent 34 years at Patton Boggs.

Pape said he started considering his options last year, during the months when Patton Boggs’ future was uncertain as it sought a merger partner.

“I had put my toe in the water a couple times over the last year and a half because it was in a sense a form of insurance because things were so tumultuous here,” he said. “It would’ve been imprudent to assume the firm was going to make it. A lot of us checked things out as a plan B.”

A Squire Patton Boggs spokesman said the firm wishes Pape well.