Lars Holman Hydle is 37. He's been a career diplomat for 13 years and has seen service in Saigon and Belfast. At present, he's assigned to Washington - one of thousands of anonymous young Foreign Service officers trying to climb the rungs of the State Department bureaucracy toward an ambassadorship.

Sally Angela Shelton is 33. She's been at the State Department fewer than six months, having gone there from six years on Capitol Hill as an aide to Sen. Lloyd M. Bentsen (D-Tex.). But she has a position - deputy assistant secretary of state for Latin America - that gives her an important role in the making of U.S. foreign policy.

The two have never met. But they have much in common. Both are bright, articulate, highly educated people, with a passionate interest in foreign affairs and a strong desire to serve their country and humanity through diplomacy.

Yet, despite this similarity of purpose, the two could almost be described as adversaries. Each has become a highly visible symbol of the opposing sides in a situation that has touched a sensitive nerve within the State Department and that could cause problems for President Carter's conduct of U.S. foreign policy.

At issue is the growing conviction of large numbers of career Foreign Service officers like Hydle that the Carter administration has bypassed them and placed a disproportionate share of policy-making power in the hands of outside political appointees like Shelton.

It's not a new criticism. Similar charges have been made against every presidential administration of the postwar period. But, largely because many department professional had been led by Carter's campaign rhetoric to expect something different, what they perceive as the reality of his performance in office has caused especially keen disillusionment among the almost 9,000 members of the career Foreign Service.

That this resentment exists has been made increasingly clear by the American Foreign Service Association, the career officers' professional organization headed by Hydle.

When Shelton was named to her position last summer, AFSA formally protested to Secretary of State Cyrus R. Vance that the appointment was "particularly unwelcome" because it bypassed many senior career officers who, in AFSA's view, had greater experience and superior qualifications.

On Dec. 9, the attack escalated, when Hydle seized the occasion of AFSA's annual awards presentation ceremony to lob some verbal hand grenades at an audience that included some of the department's top executives and Carter's national security affairs advisers, Zbigniew Brzezinski.

In a bitingly critical speech, Hydle pointed out that Carter had praised the Foreign Service lavishly while running for President. Then, he charged, after assuming office, the President and his top policy-makers had ignored the professionals, often with the excuse "that they cannot carry out the administratiion's policies because of bureaucratic obstacles raised by career officials."

"This is a tired old line, repeated during every administration by people seeking to explain away their own failures and to justify the hiring of their friends," Hydle said. "We expected better of this administration."

Outwardly, it sounded like an old complaint. But a close examination of Hydle's remarks and the arguments made by other career officers, indicates that their dissatisfaction with Carter involves different considerations than was the case under earlier administrations.

In the past, the career service's anger was directed mainly at the tendency of successive Presidents to parcel out ambassadorships to cronies and big campaign contributors, often recipients' qualifications.

The career people aren't unrelievedly happy about Carter's ambassadorial appointments. AFSA, for example, publicly opposed five of them as obvious payoffs to people who had contributed or raised substantial sums for Carter's campaign.

But, they concede, Carter, through his use of a citizens' advisory panel to screen ambassadorial nominations, has done a better job than his predecessors. A recent analysis by AFSA shows that 25 per cent of the 118 U.S. missions abroads are currently headed by political appointed appointees, as opposed to 33 per cent a year ago and an average of 36 per cent over the last 45 years.

In addition, many of Carter's non-career appointments among them former Senate Majority Leader Mike Mansfield (D-Mont.) to Japan, former United Auto Workers President Leonard Woodcock to China and former Yale President Kingman Brewster to Britain - have won praise from career officers.

However, while the career people judge Carter to have improved on the record overseas, they render a very different verdict on the question of appointments to key policy-making positions at departmental headquarters in Washington.

In an age when jet travel and instant communications have reduced greatly the autonomy and importance of ambassadors, Washington increasingly has become the center of decision-making power in foreign policy. As every career officer knows, the people with the biggest influence on policy are those who hold the key jobs at the State Department and related agencies.

Yet, under Carter, only six of the department's 25 top jobs have been filled by Foreign Service professionals. A year ago, they held 16 of these positions.

The resentments caused by that situation have been greatly aggravated by two factors. One is the fact that a recent federal executive-level pay raise, coupled with an easing of the Foreign Service's formerly stringent retirement rules, has left the department with more senior officers on active duty than it has room for.

"The result," one says bitterly, "is that you have a lot of very experienced, very qualified people in the position of collecting big salaries while they wander around pleading for assignments or cutting out paper dolls on make-work projects."

"It doesn't help their self-esteem," he adds, "when they see jobs for which they've been preparing throughout their entire working lives going to outsiders, without their even getting a chance to bid for them."

A less obvious, but potentially even more annoying foactor involves the kind of people who have been brought into the department from the outside.Many are relatively youthful men and women whose thinking was shaped by the turbulence and rapid social change of the past decade and who, for the first time, are now bringing their ideas to bear on the governmental process.

Inevitably, the perceptions and operating styles of these newcomers have tended to grate on many career officers, particularly those of the old school. The results have been evident in a number of areas - in clashes between traditional diplomacy and new notions like human rights, in disagreements over affirmative action efforts to recruit more women and minorities into the department, even in animosities produced by the lingering fallout from the Vietnam war.

In his Dec. 9 speech, Hydle recognized the need for both sides to bridge the gap between them. He even saluted the newcomers as "the best and the brightest veterans of such successful moral crusades as the civil rights and antiwar movements."

But he also stressed the feeling in career ranks that the new people often seem to regard themselves as having a monopoly on virtue. Zeroing in on Carter's controversial championing of human rights, Hydle charged: "Some senior officials seem to regard criticism of the human rights policy, or caveats about its implementation, as bordering on immorality or disloyalty to the administration."

"My purpose," he said later, "was not to attack the human rights policy but to criticize the intolerance of some of its advocates. Many of our officers find that if they bring up considerations that might militate against a tough human rights stance in certain cases, they get looked at as though they're somehow less moral than the new people."

That, and other criticisms, are rejected by those on the other side. For example, one senior official involved in implementing the human rights policy says: "The idea that we consider it disloyal or sinful to criticize the policy is totally wrong. I don't know anybody here who would view discussion of our human rights tactics as immoral. We won discussion and full exploration of all sides of the issue."

Richard M. Moose, oppointed by Carter to be assistant secretary for African affairs, argues that much of the current tension and unhappiness will be erased by the passage of time. He says:

"You have to look at the beginning and the end of an administration. In the beginning a new President wants to get his policies established, and he's naturally going to rely on outsiders whom he knows and trusts. By the end, though, the career and non-career people have become used to each other; the policies have been established, everyone knows what's wanted, and inevitably, you find a lot more of the career regulars in the key slots."

Others point out that numerical breakdowns of who holds what jobs don't tell the whole story. For example, they point out, Philip C. Habib, a career officer who holds the third-ranking post of under secretary for political affairs, is generally regarded as having an influence on policy decisions second only to Vance.

Similarly, the consensus within the department is that, among the assistant secretaries, the two with most clout are both career men: George S. Vest, who heads European affairs, and Alfred L. Atherton Jr., who oversees Middle East policy.

In addition, the dividing line between the career and non-career people isn't quite as sharp as some claim. Almost all the outside appointees have strong backgrounds in foreign affairs, and some literally wear the old school tie.

Moose, for example, was a Foreign Service officer for 10 years before resigning to work with the National Security Council and then as a senior staff member of the Senate Foreign Relations Committee.Richard Holbrooke, assistant secretary for East Asia and the Pacific, and Anthony Lake, chief of the policy planning staff, also are former Foreign Service officers.

Still, there's little question that a gulf does exist between the career service and the outside appointees. In many respects, it is perhaps best illustrated by the Sally Shelton case, partly because hers was the appointment the career people found most difficult to swallow and partly because it touches so many of the bases being contested by the two sides.

The Shelton appointment was clearly an affirmative action one, made in response to pressures to put more women in high-level foreign policy jobs. As a result, the criteria applied to her selection unquestionably were different from those that would have been used for a mole candidate.

Originally, she was slated to become ambassador to El Salvador. However, Vance switched her into the deputy assistant secretary's job after an outbreak of terrorism in El Salvador convinced him that someone with experience in running an embassy was needed there.

AFSA immediately found her unsuitable for either post. In opposing her, AFSA likened her appointment to the 1974 case of Stanton Anderson, a young Nixon administration official whose nomination as ambassador to Costo Rica was withdrawn after it stirred Senate opposition.

However, the comparison was neither accurate nor fair. Anderson came under fire because he had no foreign experience and had been involved in partisan political activities of a questionable nature. By contrast, Shelton has been studying or working in the foreign policy field throughout her adult life.

She is a Phi Beta Kappa graduate of the University of Missouri, has a master's degree from Johns Hopkins School of Advanced International Studies and also studied in Europe on a Fulbright fellowship. In addition, she speaks Spanish, French and Italian.