Tens of thousands of Palestinians rally in Hamas-controlled Gaza to celebrate the anniversary of Fatah's founding. Thousands more in the Fatah-controlled West Bank cheer on Hamas. The Palestinian public yearns for unity -- and once again Egyptians are talking about a reconciliation conclave in Cairo within two weeks.

What's going on? Could we be witnessing a historic shift toward Palestinian unity? Is there finally a basis for a meaningful Hamas-Fatah deal that might bind up the self-inflicted wounds of the Palestinian people and strengthen their leverage -- if not in negotiations with Israel, then at least in the PR battle against it?

Not likely.

Yes, Israel throws up plenty of obstacles to peace -- its settlements expansion in the West Bank is a big one. But on the Palestinian side, the greatest challenge remains the pesky problem of Noah's Ark. Simply put, the Palestinian national movement has been too successful: It has two of everything -- constitutions, mini-states, security services, funding streams, and patrons.

The absence of a monopoly, or anything close to it, over guns, people, and negotiating positions is the single greatest threat the Palestinians face to the fulfillment of their own aspirations.

And here's the kicker. Even if real unity were achieved, it would likely leave the peace process worse off -- in large part because neither Israel nor the United States would likely accept the new parameters of a Palestinian entity that included Hamas for negotiating a two-state solution.

The idea of unity resonates powerfully within Palestinian society. It's a major psychological blow to see your national movement at war with itself while the real adversary -- Israel -- exploits your weaknesses and divisions.

And yet, the Palestinian national movement has always been divided. Yasir Arafat used to tell us that it was really Palestinian democracy in action. And to a degree, given the challenges Arafat faced -- managing a fractious movement that lacked a secure territorial base and was vulnerable to manipulation by Arab states and Israel -- a decentralized structure was inevitable. Unlike other national movements, such as Algeria's FLN or even the pre-state Zionist underground, there was never a watershed moment when one faction imposed its will on the others.

There was a price to be paid for this lack of control. In June 1990, the United States suspended its dialogue with the Palestine Liberation Organization when a small Iraqi-backed group launched an attack against Israel that Arafat refused to condemn.

But Arafat was able to manage this gaggle through his iconic stature in the Palestinian national movement. Beginning with the 2000 intifada, however, as Fatah began to split and smaller offshoots like the al-Aqsa Martyrs' Brigades and Islamists began to run their own operations, his authority began to wane. His death in 2004, the corruption in Fatah, the inability to end the occupation, and the rising power of Hamas made a mockery of the idea of a unified Palestinian national movement.

The Palestinian Humpty Dumpty had finally fallen off the wall. And since Hamas's 2007 takeover of Gaza, there have been at least four unsuccessful efforts to put it back together again. Here's why unity efforts keep falling short -- even while all Palestinians say they desperately want them to succeed.

Neither Hamas nor Fatah is really serious: Unity is again being driven by tactical considerations, not by a sincere desire to unify ranks. Hamas's successful rocket attacks against Israel and Abbas's success in winning observer-state status at the United Nations allows each to come to the table with some leverage.

But the impulse to do so is driven far more by public opinion and Egyptian pressure than by any real desire to pay the price for what a real merger would entail. Hamas isn't going to give up the gun and recognize Israel -- and Abbas knows that his whole reason for being, not to mention his international support, will evaporate if he signs on to a hard-line program.

The differences are enormous: The Fatah-Hamas reconciliation accord signed in May 2011was never implemented -- nor is it, or anything like it, going to be.

Hamas is the religious manifestation of Palestinian nationalism; Fatah represents a more centrist, secular version. But the issues that divide them aren't just about seats in a parliament or who is the titular prime minister. At its core, the divide is over what Palestine is, where it is, and how its establishment is to be achieved: A secular or religious state? A state on the June 1967 borders, or over all of historic Palestine? Do Palestinians negotiate with guns or without them? Hamas may have pragmatists and hardliners on these issues. But that's the point: There is no real consensus, and given Hamas's own timeline, no urgency to produce one. And now with friendly Islamists rising in the Arab world, there's less of a rush.

The peace process in a box: Any kind of unity between Hamas and Fatah -- except one that compels Hamas to give up the gun, accept Israeli's right to exist, and defers to Abbas's authority -- will bury an already comatose peace process. Bringing Hamas into the PLO or a unity government with its current positions intact will compel the United States to cut aid to the PA, make it impossible to get negotiations with Israel launched. and give those in Israel who aren't terribly interested in the peace process an unassailable reason to just say no. Unity will make Abbas radioactive, too.

Three states: Like the two-state solution itself, real Palestinian unity is too important for Palestinians to abandon but too complex to realize. And these days, without the prospect of serious Israeli-Palestinian negotiations, it's one of those pastimes -- like the battle to win hearts and minds in the international arena -- that Palestinians will devote more time to.

Another powerful patron, President Mohamed Morsy's Egypt, also has an incentive to keep unity talks alive. After all, Hamas was derived from the Muslim Brotherhood, and looks increasingly to Egypt for support. But Morsy wants above all else to control this often unruly member of the family.

Morsy is no peacenik. He barely can bring himself to utter the words Israel or the two -state solution. But making a run a Palestinian unity, like his work at orchestrating a Gaza ceasefire, is good for his prestige and will keep a volatile issue on the back burner as he deals with pressing issues closer to home.

And if almighty Egypt wants to try, Palestinian leaders can't afford not to play along. Hamas needs Cairo to open up Gaza economically and to exert pressure on Israel. Abbas knows there's no going back to the good old days with Mubarak, but he too wants to stay on Egypt's good side. And so unity talks will start, stop, start again, and perhaps even result in a formal accord.

But beneath this faux process, the players will continue to dig in their heels. And that means further consolidation of Hamas's authority in Gaza, further settlement activity by Israel in the West Bank and Jerusalem, and Abbas hanging on to his fiefdom over Ramallah and a few other towns. He may be facing a terrible economic and fiscal situation, but neither the Americans, the Israelis, or the international community will let him go under.

John Kerry -- a man who really does believe in diplomacy -- will want to do something serious on the Israeli-Palestinian issue because he believes it's important, because others will urge him to, and because that's what secretaries of state are supposed to do. But he'll have to deal with the Noah's Ark problem. Since he's not suicidal, he won't open up a dialogue with Hamas -- but dollars to donuts says he'll start talking to the Turks, the Egyptians, the Qataris (all led by Islamists with influence in Gaza) about ways to influence the organization.

Good luck to him. To paraphrase JRR Tolkien: It will not be one or two states to rule them all, but for now three -- Israel, Gaza, and a part of the West Bank, all trying to manage in the most imperfect of neighborhoods.

To be sure, this fellowship won't last. But from the perspective of three very important powers -- Egypt, Israel, and Hamas's leaders in Gaza -- it sure beats another war or a two-state solution. The first may yet come. And the second? Well, the second is the stuff of which dreams are made.