Boston-based Bingham McCutchen plans to acquire the ailing D.C. law firm Swidler Berlin by the beginning of next year, a Bingham spokesman confirmed today.

The deal awaits approval by both partnerships, and due diligence is not yet complete, but this week the two firms signed a letter of intent to merge.

“We are optimistic about bringing this transaction to completion,” Bingham Chairman Jay Zimmerman said in a statement.

The match would instantly give the 850-lawyer Bingham � which is known for corporate work � a substantial Washington presence, more than tripling the firm’s 55-lawyer D.C. office.

Zimmerman says he was drawn to 140-lawyer Swidler because the firm would add three key practice groups, telecommunications, real estate finance and lobbying. A spokeswoman for Swidler said Managing Partner Barry Direnfeld was not available to comment.

One key group at Swidler is already out of the deal, the firm’s insurance policy group headed by Mark Plumer, which has client conflicts with Bingham’s insurance group, Zimmerman says. The future destination of Swidler’s bankruptcy group, headed by former Managing Partner Roger Frankel, is also still unclear.

For Swidler, the merger with Bingham comes at the end of a long downward spiral. Last year the firm was rocked by failed talks with both Dickstein Shapiro Morin & Oshinsky and Orrick, Herrington & Sutcliffe. In January its entire New York office defected to Dechert, and key D.C. partners in its antitrust and white-collar practices jumped ship almost simultaneously. Then this summer, its 14-lawyer energy group left for the D.C. office of Alston & Bird.

In response, Swidler went on the offensive. It launched a public relations campaign to show that it remained a viable entity, running advertisements about renewing its commitment to core values. In a letter to the editor published in Legal Times last January, Direnfeld wrote that “by rejecting the option of a firm merger that involved our D.C. office, we embarked, arm-in-arm, with our New York partners on a strategy that can fairly be described as a de-merger.” But those efforts produced few tangible results.

Now, according to Bingham’s Zimmerman, the merger is in the best interests of both firms. He says he hopes that regulatory clients from Swidler’s telecommunications group will yield increased corporate work. And Bingham plans to meld Swidler’s federal lobby shop � which shares clients such as Exxon Mobil Corp. with Bingham � with the firm’s existing legislative affairs subsidiary. That practice, Bingham Consulting Group, focuses on devising state-level political strategies.

For Zimmerman, taking on Swidler “is an important next step for us. There are fewer and fewer opportunities available down here in D.C.” for mergers.

Indeed, Bingham has been eyeing the D.C. market for years. Though the firm first set up shop inside the beltway in 1981, its office remained small and largely focused on a Securities and Exchange Commission regulatory practice. In recent years, however, the office has expanded, bringing in a steady stream of new attorneys. In February the firm hired Steve Crimmins and Ivan Knauer, both regulatory and enforcement specialists from Pepper Hamilton. Two months later, the firm brought in four partners and several associates from Burns, Doane, Swecker & Mathis, including R. Danny Huntington, the firm’s former managing partner. Then in May, Bingham bolstered its consulting group with former presidential advisers Ian Alberg and Keith Brancato, from the Clinton and Bush White Houses.

Bingham is very familiar with law firm acquisitions. The firm, which has catapulted up The American Lawyer magazine’s rankings of the nation’s highest-grossing law firms from No. 81 in 1999 to No. 26 this year, grew through a series of five successful mergers. In 1997 it took in the Japanese practice of Marks & Murase, which had offices in New York and Los Angeles.

Two years later, the financial restructuring and insolvency firm of Hebb & Gitlin joined Bingham. In 2001 the firm boosted its New York office with the acquisition of Richards & O’Neil. The next year the firm swung its biggest deal to date, merging with 300-lawyer McCutchen, Doyle, Brown & Enersen, a longtime San Francisco-based firm. In 2002, Bingham acquired Los Angeles-based Riordan & McKinzie, the firm co-founded by former Los Angeles Mayor Richard Riordan.

Bingham has a lot of reach to offer a mid-size firm like Swidler. With 11 offices straddling both coasts, the firm boasts strong profits per partner of $1.1 million, roughly the same as Swidler’s $1,070,000.

Emma Schwartz and Jason McLure are reporters with Legal Times, a Recorder affiliate based in Washington, D.C.