When it comes to professionalism among Washington's diplomatic community, the award usually goes without demur to the Israelis, who are known for carrying out their duties coolly, deftly and persistently whatever crisis may afflict their government.

But on Monday, 15 Israeli staff members became the first envoys to go on strike in Washington. Their desks went unmanned, phone calls did not get returned, reports did not get filed and the telex machine was silent.

The striking diplomats, who returned to work Tuesday, were participating in a strike by foreign ministry workers back home protesting the lack of compensation for long working hours, hard-won language skills and the personal dangers faced by Israel's representatives abroad, according to one striking embassy employe who asked not to be named.

They were also protesting what they feared would be an increase in the number of political appointees rather than career diplomats to ambassadorships.

Outside the embassy, the strike was barely noticed. The switchboard operator, who conceded it was "an unusual situation," said she was able to route all calls for the striking diplomats -- who included ministers, counselors and first secretaries -- to nonstriking economic and military personnel.

The intangibility of diplomats' accomplishments, which often leads outsiders to suspect they don't do much all day long, also made it difficult to assess the practical effect of the strike.

When asked what that effect was, one striking employe replied, "I don't know. It's a good question. In diplomatic work you don't see any outcome, any results, at the end of the day. There are no cars in the lot waiting to be sold, no meat to send to market. There were no meetings, no phone calls, no reports, whatever a diplomat does was not done."

Ambassador Moshe Arens did not participate in the strike and made it clear he opposed it, the same employe said.

Though the Israeli Embassy is the first to be hit by a diplomatic strike, at least two others here have had problems. Last June, about 70 employes of the French Embassy, mostly secretaries, stopped work for three hours to protest the declining value of their French franc paychecks due to the strengthened dollar.

In 1980, the support staff of the Canadian foreign service went on strike and its members here picketed the embassy.

Yesterday, although foreign ministry offices in Israel remained closed, the embassy here had returned to normal. "It's good to be back at work," one striker said. Then, showing he still had the diplomat's touch with understatement, he added, "It's a challenge to be in Washington these days."