Possible meanings are 1) the Jewish leaders do not believe that Jesus saved others or that he can save himself, or 2) they believe he did save others but are laughing at him because now he cannot save himself. (See: [[rc://en/ta/man/translate/figs-irony]])
The leaders are mocking Jesus. They call him "King of Israel," but they do not really believe he is king. AT: "He says that he is the King of Israel" (See: [[rc://en/ta/man/translate/figs-irony]])