Jerusalem — A cartoon named "Supermouse" has appeared in a newspaper here affiliated with the opposition Labor Party. Its hero, who bears an uncanny resemblance to Israeli Prime Minister Menachem Begin, discovers at an early age his strong mouth, takes his elongated tongue in his hand like a weapon and uses it to settle accounts with all his opponents. When depressed, he drinks a special elixir of strength that enables him to shoot off his mouth more than ever.
Mr. Begin's sharp tongue and his propensity to use it without mercy against foreign leaders and domestic political opponents have been amply demonstrated over recent months. But his exuberant verbosity and the schoolmaster style he uses when detailing Israel's rationale for attacking the Iraqi nuclear reactor have produced some bloopers.
These, say his political opponents, create a personal "credibility gap" that could overrshadow the basic issues as international debate over the merits of Israel's raid on Iraq's Osirak nuclear reactor continues.
While at a garden party on June 10 at the home of the exiting British ambassador, John Robinson, Mr Begin repeated for 10 minutes to guests -- including journalists -- that the Israeli bombing raid had destroyed a secret chamber 40 meters under the nuclear reactor.
This bunker, he said, was being prepared by Iraq for the production of atomic bombs. Asked how it had been possible to destroy such an installation, he replied proudly, "Our bombs, which weighed 1 ton each, . . . destroyed everything."
The following day Mr. Begin admitted that he had erred. The underground bunker was only four meters underground, although he still maintained it was intended for secret work. The pro-Labor Party Jerusalem Post newspaper wrote that Mr. Begin's claim had embarrassed senior Army officers who hoped it would not damage Israel's position that the reactor had been intended for military use.
Post reporters said they believed that Mr. Begin had confused the underground room with a joint Italian- Iraqi project to reprocess uranium and separate plutonium, a project that was widely publicized. In France, the Ministry of External Relations called the story of the bunker "fantastic" and said it could only refer to a building designed for nonmilitary scientific expreriments.
The confusion was compounded by press reports, confirmed by official sources, that a quote used with flourish by the prime minister to justify the raid could not be documented. The quote was said to be from a leading Iraqi paper and announced that Iraq's nuclear program was aimed not against Iran but against the Zionist enemy. However, these sources produced other hostile quotes from Iraqi media calling for Israel's destruction.
Mr. Begin's speaking style has become an issue both in the election campaign being fought here and in the hadling of Israel's foreign relations. Mr. Begin's fighting style appears to have won him votes for the June 30 election.
In January, with elections set, a Jerusalem Post poll predicted that the Likud coalition would win 20 seats to the Labor Party's 58. But an early-June poll taken just before the raid on the reactor showed the Likud with 46 seats to Labor's 40.
Although last year Mr. Begin appeared drawn and ill, this success -- along with his strong ideological belief in a strong Israel within biblical borders -- has buoyed his style into supreme self-confedence.
The Labor Party -- and more neutral figures -- have also criticized Mr. Begin's disclosure of what they regard as military secrets often inserted flamboyantly into speeches. These include details of a planned and aborted raid to bomb Syrian missile sites in Lebanon.
Mr. Begin denied revealing any military secrets.
Mr. Begin also repeatedly stressed the presence of Soviet technicians at these missile sites, although the US State Department said there was no evidence to confirm this.
But Mr. Begin's domestic constituency appears undismayed by such apparent indiscretions. His swaying of foreign leaders such as German Chancellor Helmut Schmidt has had a favorable impact on voters.