Wal-Mart Stores, which has long cultivated a folksy, outside-the-beltway image, has hired the ultimate Washington insider as its next head of public relations and government affairs.

The giant retailer said yesterday that Leslie Dach, a prominent Democratic operative who advised President Bill Clinton during the impeachment process, would join the company in August……

The appointment indicated that Wal-Mart, which is the subject of a broad assault from union-backed groups, would push ahead with an aggressive political-style response to its critics.

That response has been heavily shaped by Mr. Dach himself, who runs the Washington office of the public relations firm Edelman.

Wal-Mart hired Edelman last year and, since then, the firm has developed a number of new public relations initiatives for the retailer, including a rapid-response war room at its headquarters in Bentonville, Ark, and an outside advocacy group called Working Families for Wal-Mart.

Mr. Dach has also bolstered Wal-Mart's once-sedate public relations team, adding dozens of Edelman consultants to its ranks.

While heading up the Wal-Mart account for Edelman, Mr. Dach has become a close adviser to Wal-Mart's chief executive, H. Lee Scott Jr., often tweaking his speeches and accompanying him to major company events.

Immediately after Mr. Scott delivered a speech about health care to the nation's governors this year in Washington, he gave Mr. Dach a bear hug in the corridor of the Marriott Hotel.

To reflect that close relationship, Mr. Dach will be given the title executive vice president for corporate affairs, will serve on the executive committee and will report directly to Mr. Scott. Mr. Dach's predecessor at Wal-Mart, Jay Allen, who has retired, held the title senior vice president and reported to a lower-ranking executive.

Mr. Dach, who lives in the Washington area, said he would split his time between Washington and Bentonville.

In an interview, Mr. Dach said he was impressed with the changes under way at Wal-Mart, like sweeping commitments to lower its energy use and carbon dioxide emissions and its efforts to expand health care coverage to its 1.3 million American workers.

“I believe that change is happening and the change is real,” he said. Explaining his decision to leave his role as an outside consultant, he added, “The changes come from the inside.”