Israel’s advance on Gaza City is not only dividing the Israeli public but also showcasing extraordinary discord between the military leadership and the elected government at a time of crisis.

Top military and security officials have been at odds with Prime Minister Benjamin Netanyahu recently over three critical policies: his decisions to take over Gaza City, the enclave’s main urban center, and to strike at senior Hamas officials in Qatar, and his approach to negotiations on ending the war.

Mr. Netanyahu’s hard-line stance on all three issues has not only deepened his isolation internationally but has also sharpened questions at home about where he is taking Israel. His actions have shaken Israel’s strategic relations with Arab states, even as President Trump wants to see those expand, and have prompted condemnation and sanctions from some traditional allies.

“We are in a unique and unprecedented era in the sense that decision-making on core issues of national security is essentially concentrated in the hands of one person,” said Yohanan Plesner, president of the Israel Democracy Institute, a nonpartisan research group based in Jerusalem.

“The norm was that big decisions were taken in consensus between the top political and top military-security leadership,” added Mr. Plesner, a former centrist lawmaker. “So this norm has been violated — the chief of staff has been forced to take his soldiers into a battle that he doesn’t necessarily believe in.”