JERUSALEM — Younger rivals in his Likud party are circling overhead. Bombshell exposés on the nightly news have returned his looming indictment on corruption charges to the forefront.

Even Benjamin Netanyahu’s undisputed advantage over every challenger, his primacy on the international stage as Israel’s longest-serving prime minister, has lately been a source of as much embarrassment as luster.

With two weeks until a do-over election that was forced on the country by his inability to form a government after coming out on top in the April ballot, Mr. Netanyahu’s larger-than-life persona may have lost something that made his re-elections once seem inevitable.

A series of recent setbacks has overtaken his aura of indispensability.

Last month, Gilad Erdan, the 48-year-old minister of strategic affairs, turned down an appointment as ambassador to the United Nations. Publicly, he said he wanted to stay in Israel to help Likud prevail in the Sept. 17 election. Privately, he made it known he did not want to be stuck in New York during a possible battle to succeed Mr. Netanyahu as party leader.