How Israel could lose:
Just do nothing differently for a few days, while the pressure builds for a cease-fire. No imaginable cease-fire agreement can close off the smuggling routes — no international force could, nor could Egypt. Even if Hamas agrees to stop rocket attacks, what can prevent it from starting them up again as soon as supplies are replenished?
An agreement would probably include some ‘humanitarian’ concessions to Hamas. Hamas will exploit them for military purposes, as well as claim that they were obtained by force of arms.
Hamas will have lost perhaps 5% of its manpower and much material. So the cease-fire that will follow — like the one that it broke to cause this war — will give it time to replace what has been lost. Any international presence will protect it in the interim.
How Israel could win:
Cut off the Philadelphi corridor along the Egyptian border and maintain a presence there. It’s the only way to stop the weapons smuggling (if only it were so easy in Lebanon). Some Palestinian civilians will have to move. Worse things have happened.
Send special forces units to al-Shifa hospital or wherever the Hamas leadership has set up its headquarters.They can come in by helicopter. All that’s needed is adequate intelligence about the layout of bunkers, etc. and after all, Israel built the hospital. Eliminate the leaders and destroy the command and control system.
Spend a few more days mopping up weapons depots and lower-level leadership. Then announce that the war is over, and invite Fatah, the UN, the US, NATO, or whoever wants to govern the strip to do so. But maintain full control over the borders and crossings.
In the long term:
Getting rid of UNRWA must be a priority. UNRWA is no more or less than a branch of the Palestinian movement, funded by the rest of the world, whose function is to produce soldiers to confront Israel (see Gunnar Heinsohn’s perceptive comments here).