As Israel gears up to add tens of thousands of reserve soldiers to the battlefield in Gaza, the logic of Prime Minister Benjamin Netanyahu appears to be this: Victory against Hamas will come from an even bigger barrage of military might in the weeks ahead.

“We have not finished the war,” Mr. Netanyahu declared on Sunday as his security cabinet signed off on expanding the fighting. “We will perform this operation with a unified military, with a powerful army and deeply resolved soldiers.”

But it is not clear how those additional fighters will fundamentally alter a dynamic seen over 18 months of war in which hundreds of thousands of soldiers have pummeled Hamas fighters, with residents in Gaza caught in the middle, but have failed to achieve Israel’s goals of destroying the militant group or releasing all hostages.

And it remains uncertain whether the Israeli military will surge back into Gaza before President Trump arrives in the Middle East next week for meetings in Saudi Arabia, Qatar and the United Arab Emirates. Two reservists who spoke on condition of anonymity because they were not authorized to make comments to the news media said that they had received call-up orders beginning in June.

Israeli military forces near the border with Gaza on Sunday.Credit…Menahem Kahana/Agence France-Presse — Getty Images

Since the collapse of a two-month cease-fire in March, Israel has blocked food, medicine and other humanitarian aid from reaching Gaza. And the Israeli air force has already renewed its heavy bombardment of the enclave.