Jerusalem — Ariel Sharon, Israel's controversial Cabinet minister, may score a political victory back home even if he loses his $50 million libel suit against Time magazine.
That is the analysis of political observers who dismiss as ''irrelevant'' the mounting criticism here of Mr. Sharon's long stay in New York while he pursues his case.
The suit, which is being followed closely by the press both here and in the United States, is designed to further the irrepressible Sharon's single-minded goal of becoming prime minister, his detractors say. His supporters say he is defending the honor of the Jewish people.
Sharon is now locked in a three-way battle with former Prime Minister Yitzhak Shamir and Cabinet minister David Levy for leadership of the Herut Party. Herut is the chief member of the rightist Likud coalition that shares power in the Labor-led government.
The combative Sharon's case against Time, analysts here say, has enhanced his position within Herut and increased his chances of taking control of the party next year if, as expected, it elects a new chairman to replace the retired Menachem Begin.
''It makes him look strong, and they want a strong man. In any case, this trial will serve his (Sharon's) cause within the Herut movement,'' said Arye Naor, a former Begin Cabinet spokesman and vocal critic of Sharon. ''He's interested in first of all winning that leadership struggle.''
Sharon is suing Time over an article the magazine published in February 1983. According to the article, Sharon had reportedly discussed with the Gemayel family the ''need'' for Lebanese Phalangists to ''take revenge'' for the assassination of Lebanese President-elect Bashir Gemayel.
Sharon's conversation, Time reported, took place shortly before Phalangist militiamen massacred Palestinian refugees in the Sabra and Shatila camps near Beirut in September 1982.
The fiery Sharon, who was Israel's defense minister during the 1982 invasion of Lebanon, was subsequently forced to resign his post when a state commission held him to be indirectly responsible for the massacre of 700 to 800 Palestinian refugees.
He soon made a political comeback, however, coming close to wresting control of the Herut Party from Mr. Shamir earlier this year, and winning an important Cabinet post in the Labor-Likud coalition government.
Sharon has accused Time of being ''one of the centers of anti-Semitism in the world.'' He has said that he brought his suit to defend what he has termed the magazine's ''blood libel'' against the Jewish people.
But fellow Cabinet ministers and political opponents have criticized Sharon in the Israeli press for his conduct since the trial began.
Sharon, who is minister of industry and trade, has been taken to task for being away from Israel for a month during the nation's worst economic crisis in decades. He has also been criticized for staying beyond the two-week leave granted by Prime Minister Shimon Peres, and for staying at the expense of the government. There have been public demonstrations, urging Mr. Peres to fire Sharon.
The influential Hebrew-language daily Ha'aretz blasted Peres for approving state financing for Sharon's stay, which the newspaper said had cost Israeli taxpayers $100,000 to date.
''But some will say,'' the newspaper noted ironically, ''that if this is all - we have come out of this one of the minister's capers cheaply: Operation 'Peace for the Galilee' has cost $2.5 billion.'' The paper was referring to Israel's June 1982 invasion of south Lebanon, which it still occupies.
The criticism hit a new high this week when two attempts were made to bring legal action against Sharon.
Wednesday, the leftist Mapam Party failed in its call for the parliament to launch a criminal investigation into two military decisions Sharon allegedly made during the Lebanese invasion without Cabinet approval.
Also on Wednesday, the left-of-center Citizens' Rights Movement petitioned the High Court of Justice to order the prime minister to demand Sharon's return to Israel. The petition was referred to a three-judge panel.
Last month, Communications Minister Amnon Rubinstein demanded that Sharon resign as minister of industry and trade if he wanted to continue his lawsuit against Time. Another Cabinet minister, Mordechai Gur, labeled Sharon a ''cholera.''
But Peres has not moved against Sharon, who has publicly criticized the prime minister and the Labor Party for allegedly aiding Israel's enemies by not supporting his case against Time.
Strict voting discipline was enforced Wednesday on Labor members when Mapam's effort to open a parliamentary investigation of Sharon was voted down.
Labor leaders in parliament required all Labor members to strike the motion from the Knesset's agenda.
Peres seems determined, at least at this juncture, to preserve the fragile unity government. Sources within the Labor Party say the prime minister is exasperated by Sharon, but does not want to cause a crisis in the government. The prime minister remains cautious because of Sharon's popularity, particularly among young and Sephardic voters (Jews from African or Arab countries).
A recent public opinion poll on who would be most suitable as defense minister showed a slight increase in Sharon's popularity from August to October. Sharon came in second - behind Defense Minister Yitzhak Rabin - both in August and in October. But Sharon was selected by 19.8 percent of respondents in October, up 2 percent from the August poll.