Updated: July 1, 7:54 p.m.

Patton Boggs, a perennial lobbying and legal powerhouse, announced Thursday that it has acquired the Breaux-Lott Leadership Group, the politically connected boutique lobbying shop.

“This acquisition is a strategic coup and a cornerstone for our bipartisan growth,” Thomas Hale Boggs Jr., the chairman of Patton Boggs, said in a statement.

The top partners in Breaux-Lott, former Sen. John Breaux (D-La.) and former Senate Majority Leader Trent Lott (R-Miss.), will become senior counsel at Patton Boggs.

“We will continue to provide boutique-level personal attention to our clients with the added benefit of the wide-ranging policy, legal, and business services that only Patton Boggs can provide,” Breaux said in the statement. Breaux had worked at Patton Boggs before partnering with his former Senate colleague.

“This is an exciting opportunity to expand our firm with the resources of one of the most respected and revered law firms in the nation,” Lott said.

Patton Boggs has routinely been among the top firms in Washington in terms of lobbying revenue, generating $6.3 billion in fees since 1998. The firm drew $412.4 million in lobbying revenue last year, ranking just behind Akin Gump Strauss Hauer & Feld.

Breaux-Lott generated $74.8 million in lobbying revenue in 2009. While Breaux-Lott was small, it was efficient based on its revenue and number of employees. The firm ranked second recently in a Roll Call study of lobbying firms with the largest receipts per lobbyist. Breaux-Lott generated $1.35 million on average for each of its eight registered lobbyists last year.

Some conflicts will keep Patton Boggs from taking over all of Breaux-Lott’s clients. For example, according to lobbying registrations of foreign countries filed with the Justice Department, Patton Boggs represents the Embassy of China, while Breaux-Lott represents the government of Taiwan.

Negotiations on the acquisition began seriously several months ago, according to Stuart Pape, a managing partner at Patton Boggs. But Pape added that because Breaux had previously been at Patton Boggs, there had been ongoing conversations throughout the years.

He said that Breaux-Lott employees will be brought over to Patton Boggs, including Breaux’s son, John Breaux Jr.; Lott’s son, Chester Trent Lott; three public policy advisers; and three staff members. Patton Boggs would not release the financial terms of the acquisition, which takes place immediately.

“The deal is done,” Pape said.

Alex Knott contributed to this report.