A 21-year career in the U.S. Foreign Service has probably given William S. Shepard some useful skills for dealing with Montgomery County's fractious Republican Party as he runs for Congress.

Spurned by much of the local GOP's liberal activists, who are supporting state Del. Constance A. Morella, Shepard has turned to the more conservative wing of the party for support in his primary battle against the popular Bethesda lawmaker.

Shepard, 50, who returned to his Potomac home last year after serving many years abroad, has mounted a spirited attack on Morella, calling her a "carbon copy" of the several Democrats vying to succeed Rep. Michael D. Barnes and criticizing her for avoiding a one-on-one debate of the issues.

He was particularly incensed by her successful behind-the-scenes campaign to win the coveted endorsement of the National Republican Congressional Committee, which Shepard also had sought. Shepard charged that by capturing the endorsement, Morella was effectively ignoring the concerns of voters.

Morella has dismissed her rival's complaints, calling them "desperation moves to get some publicity."

Publicity and money would surely help Shepard, who has never been a force in local Republican circles and is now struggling to compete with Morella's fund-raising. His wife, Lois Burke Shepard, was a Reagan-Bush campaign worker and chairwoman of a group known as Republicans Abroad, the voter registration arm of the Republican National Committee's voter registration arm for Republicans living outside the United States.

It remains unclear whether Lois Shepard's ties to the Reagan White House will help her husband, particularly in view of the support that Morella enjoys from national GOP committee members Helen Chamberlain and Richard Taylor, not to mention local party luminaries such as retiring Sen. Charles McC. Mathias Jr.

Shepard, a tall, handsome man with a baritone voice -- Hollywood agents would cast him as a diplomat -- received degrees from Wesleyan University and Harvard Law School, served three years in the U.S. Army and was stationed in five countries for the Foreign Service. He was the U.S. Consul General in Bordeaux, France, until he retired last year.

Shepard is campaigning on a variety of national and international issues calling for tough new intitiatives to counter terrorism around the world.

He is also focusing on matters close to home. Having already opened a headquarters in Bethesda, Shepard was set to open a upper county office in Gaithersburg this week.