Let's talk about the end game in Gaza. I have since this operation began said that Israel's goal cannot be the cessation of rocket fire from Gaza. The very moment that the last Israeli soldier who entered during this conflict leaves Gaza, rockets will be launched into Israel. It is like children fighting about who will have the last word. Hamas will have the last word, or Islamic Jihad, or frankly, some unknown guy who happens to have been a part of a rocket squad and knows where to find or how to make a rocket.
Israel's goal cannot possibly be to leave Hamas in power with any long term ability to increase that power and I would argue strongly that it cannot leave it in power with any long term ability to maintain power at all. Further, IF Israel gets to a point wherein it finds itself needing to withdraw, I see no reason whatsoever that it should not change the rules on the ground in Gaza first.
Why is Israel not bringing Fatah back into Gaza? Why not say, "We will not negotiate with Hamas at all? We will only negotiate with the leadership of the Palestinian Authority?" Why not empower the PA? Only negotiate with the PA? If there is a true civil war in Gaza, why not help the side you prefer? I would suggest that Israel demand that the PA reoccupy Gaza before it withdraws a single soldier. Why not have an entire force of Fatah allied troops enter Gaza under Israeli cover into the areas under Israeli control now? Why not demand as Egypt did that the PA take control over all of the border crossings? Let Fatah battle Hamas. If the answer is that the PA can't or won't, SAY THAT publicly. Better yet, hold a press conference with Abbas and demand that he say it publicly. There is no reason for Israel to protect an entirely failed governmental system from scrutiny.
If the PA is not willing to reenter Gaza, the first result would then be the nullification of all previous agreements. Furthermore, the result would be either a far stronger Hamas, not worried about being removed from power, or a power vacuum that could well be filled by another of Israel's enemies. The end game cannot simply be Israeli withdrawal. It must be stability in Gaza or at least instability with the hope of attaining stability.
Leaving Gaza without removing Hamas or at least weakening Hamas so much that it cannot hold power for long would be catastrophic both the hopes for peace and for the Palestinian people who will have no hope of improvement in their lives. Will Israel be MORE inclined to relax border control after the event if Hamas stays in power? Hardly. Life would be terrible and Hamas needs it that way in order to maintain control. Things will get worse, not better, for the average Palestinian. Now what is required to weaken Hamas so much that it cannot hold power?
That is relatively easy to answer. Israel has already accomplished some of it. First, removal of Hamas' ability to control the Egyptian border and to smuggle. It is not weaponry that keeps Hamas in power, but its ability to smuggle in other things and to functionally prop up the economy through clandestine efforts that bring it income while at the same time destroying the hope of others to acquire prosperity by means outside of Hamas' control. If the borders were truly open and goods could truly flow, Hamas would be far weaker. It is therefore in Hamas' interest to threaten Israel's security to the point that it must shut its borders. By removing Hamas' supply lines, you eliminate the financial and political gain obtained by forcing Israel to shut the borders.
Second, in order to weaken Hamas, you need to empower an alternative. Right now, I know of only one, the PA. The PA must be brought back into Gaza and given enough support not only to defend itself but to further weaken Hamas. The PA also must be empowered with funds and goods so that it can undermine Hamas' control of the economy.
The real question is not "Is there a desire to create a lasting peace?" but instead "Is there a will to make it happen?" The answer to the first question is "Yes." I'm not sure what the answer to the second question is.