On the flip side, if he weighs in with an indictment during the campaign, he could be seen as trying to sway the election. The alternative, however, would be keeping voters in the dark about whether a leading candidate is on the brink of being charged with a crime.

Critics have accused Mr. Mandelblit of foot-dragging in the cases concerning the prime minister. Mr. Mandelblit says he will make a decision as soon as possible.

People Power vs. the Law

If Mr. Netanyahu is indicted, legally he can continue to serve as prime minister while he is a defendant. An accused prime minister is not obligated to resign until a final conviction in court.

But if he were charged, critics would probably petition the Supreme Court to force him to step down. The Supreme Court has ruled that a cabinet minister charged with a crime must step down. The judges would have to decide whether the same standard applied to the prime minister.

If, at that point, Mr. Netanyahu had been re-elected, he could make a political argument to bolster his legal one. That argument, says Amit Segal, the political analyst of the Israeli television News Channel, “would be: More than a million voters knew exactly what the charges were against me and yet they elected me again.”

Then, the Supreme Court would be faced with the prospect of reversing the will of the voters.

“That’s why Netanyahu desperately needs to be re-elected,” Mr. Segal said in an interview on Monday. “For him, the next election is not only a political challenge. That’s the least of his worries. First and foremost, it’s a legal one.”

There has also been speculation in the Israeli news media over the possibility of Mr. Netanyahu reaching a deal, if he is prosecuted, in which he would step down or not run again in return for avoiding jail time.