JERUSALEM — As Israelis digested the accusations of fraud, bribery and breach of trust leveled against Prime Minister Benjamin Netanyahu, the question on the minds of many Friday was whether the scandal could spell the beginning of the end for Israel’s long-serving leader.

Attorney General Avichai Mandelblit’s decision Thursday recommending the indictment of Netanyahu, pending a hearing at which he can present his defense, came just six weeks before the general election set for April 9.

The first opinion polls conducted since that recommendation showed the prime minister taking a small but significant knock in his bid for reelection, as his main rival gained.

A poll taken by Israel’s national broadcaster Kan projected that Netanyahu’s Likud party would win 29 seats in Israel’s 120-seat Knesset, or parliament, down three from what was predicted a week ago. His main rival, the Blue and White party, extended its lead to 37 seats. 

Channel 13 put Likud at 30 seats.

“Bibi,” as Netanyahu is known to many Israelis, has defied the polls to win elections in the past but may struggle to form a coalition if he wins. On Friday, for the first time, the center-left bloc of his rivals was polling ahead of Netanyahu’s right-wing coalition.

He has shown no sign of stepping aside voluntarily, but there are growing calls for him to do so.

In a televised speech Thursday evening, after news of Mandelblit’s recommendation emerged, Netanyahu vowed to continue serving “for many years.”

He urged the public to resist being confused by the “witch hunt” and promised that the “house of cards” of the three corruption cases against him would soon collapse.

If he does manage to win at the ballot box and for a coalition, Netanyahu could complete his fifth term in office. Israeli law does not require him to step aside unless he is convicted and all appeals have been exhausted.

That legal process could stretch for years. In the case of former prime minister Ehud Olmert, seven years passed after the initial announcement of his indictment on corruption charges before he exhausted his appeals and was jailed. Olmert, however, had stepped down as prime minister before the attorney general announced a decision to indict.

At the time, Netanayhu was among those who argued that Olmert’s legal woes were too much of a distraction for him to govern. Now, Netanyahu’s rival Benny Gantz, who joined with Yair Lapid to form the Blue and White party last week, is making the same argument.

“Wake up, think about the national responsibility and resign,” Gantz, a former army chief of staff, said Thursday.

His call was followed by others.

“Netanyahu cannot continue to serve as prime minister. He knows that,” Lapid said. “He knows that better than anyone.”

The center-left Labor Party held a protest outside the prime minister’s official residence in Jerusalem on Friday, saying it was a “black day for Israel” and calling for Netanyahu to step down. And Tamar Zandberg, chairwoman of the left-leaning Meretz party, said he should immediately withdraw from the election.

But Netanyahu’s coalition partners have pushed back. Some released statements saying they would join a government led by him even if he is indicted.

“Netanyahu has the presumption of innocence like any other citizen in the country,” Education Minister Naftali Bennett said.

Netanyahu’s Likud party said in a statement that it would launch its official election campaign next week and that the prime minister, who remains atop the party’s ticket, was strategizing with candidates.

He has also received words of support from President Trump, who praised the “great job” he has done as prime minister and called him tough, smart and strong.

“Trump can’t save Netanyahu, but in a close election, the kosher seal of approval by a guy who’s probably more popular in Israel than Netanyahu after today might help,” said Aaron Miller, vice president at the Woodrow Wilson Center and a former State Department analyst and negotiator. 

Netanyahu faces potential charges in three investigations.

In the first, Case 1000, Netanyahu is accused of fraud and breach of trust for allegedly taking lavish gifts in return for political favors.

In the second, Case 2000, he is accused of fraud and breach of trust for an alleged deal with Arnon Mozes, publisher of the Yedioth Ahronoth newspaper, to use legislation to weaken a rival daily in return for favorable coverage.

The most serious peril appears to lie in Case 4000, in which Netanyahu faces a potential bribery charge for allegedly easing regulations to benefit Shaul Elovitch, the majority shareholder in the Israeli telecommunications giant Bezeq, in return for positive coverage on an Israeli news site.

Guy Lurie, a researcher at the Israel Democracy Institute, said that while Netanyahu could legally remain in office until his final appeal, his doing so would “put Israeli democracy under strain.”

“It is hard to imagine,” he said, “how such a thing could happen.”

Morris reported from London.