No government likes to expose its failings or misdeeds. There is particular reluctance to do so when a government feels on the defensive, as the government of Israel must surely feel in the wake of the atrocities in the Palestinian camps. Yet any democratic nation knows that its strength lies in the openness and integrity of its institutions and in its capacity for honest self-examination. This is no less true of Israel than of the United States, which has had to deal with its own aberrant acts abroad.
The Begin government's reported refusal to appoint a judicial panel to look into the Shaba and Shatila massacre will do Israel much harm. For it will tend to support the suspicions of those abroad who believe Mr. Begin and his cabinet ministers not only permitted the Christian militiamen to enter the camps - something the government has acknowledged - but fully expected them to go beyond merely arresting PLO guerrillas and cleaning out arms caches. Reports in Israeli newspapers suggest that government officials knew of the killings at least 24 hours before they began to act. The Jerusalem Post reported that the government had been advised by Israeli intelligence against letting the Christian gunmen into the camps. Many questions linger.
It is quite possible that the findings of an impartial inquiry would indict the Begin government, already so discredited in the eyes of the world. But better this than that Israel itself be thoroughly discredited for failing to apply the standards of truth it so im-passionedly calls for from other governments when it comes to the issue of the persecution of Jews. Israeli President Yitzhak Navon summoned up the best spirit of the nation when he told Israelis they had had an obligation to themselves and the civilized world to clarify everything that happened. If Israelis adhere to their ancient values of morality, justice, and truth, he commented, ''I am certain we will endure doubled in strength and draw strength to overcome all the obstacles that today are strewn in our path.''
Judging from the popular reaction in Israel to the massacres, the Israeli people agree.