First, what is not different: both fronts were triggered by a humiliating localized attack on an IDF position stationed in order to maintain a murky "status quo." Both fronts abut population centers where missile launches were either a reality or a distinct possiblity. Warfare on both fronts started with the limited goal of extracting soldier-abductees; the Israeli military goals in both instances then took on a life of their own, with (in the case of Gaza, the undeclared) purpose of destabilzing the government which either materially participated in or sanctioned the triggering abduction, and the subsequent missile attacks on the Israeli homefront. Both fronts obliquely refer back to Damascus, and possibly Tehran; and yet, as of this writing, neither Syria nor Iran have either directly injected themselves or been drawn into the conflict. Both HAMAS and Hizbollah have compatriots in Israeli prisons, and abducting Israeli soldiers has long been a tactic for extracting them in negotiated prisoner swaps.
But there are differences: HAMAS is not Hizbollah. Let's dwell on that simple statement: HAMAS is not Hizbollah. HAMAS is now the central pillar of a Palestinian government under occupation in internationally unrecognized borders; Hizbollah is a coalition partner of an "independent" Lebanese government which enjoyed internationally recognized borders (see the UN statement of June 18, 2000), supervised by impotent UN observers who allowed southern Lebanon to become an independent and missile-tipped Hizbollahstan, while Israel and the world watched on. One of those unpleasant Middle East ironies: everyone - Israelis included - understood that Hizbollah was amassing these last 6 years an arsenal of over 10,000 missiles, the most sophisticated having been supplied directly from Iran. In other, simpler words: in the eyes of the world, HAMAS has a legitimate gripe (though its ideology & use of terror is unacceptable to a sizable portion of the world community); Hizbollah (which attacked from "sovereign" Lebanese territory) has nothing (though Hizbollah maintains that Israel holds a few hundred meters of land in the Sheba Farms area [picture of Sheba "Farms," taken by yours truly June 27], a claim not recognized by the UN).
HAMAS represents on behalf of its people the unpalatable partner in any future resolution of the Israeli-Palestinian problem; Hizbollah represents no one -- it is simply a hate-filled Iranian proxy which can never be mollified (and now we know it cannot be contained). HAMAS cannot effect a debilitating partial shut-down of the Israeli economy; Hizbollah can. HAMAS, despite all its rhetorical defiance, can conceive of a cease-fire with Israel; Hizbollah cannot. HAMAS and the Palestinian people it must represent have much to lose; Hizbollah, by firing at Haifa, is posed to make its apocalyptic last stand, and is bringing down Lebanese society in the process. It has nothing left up its sleeve, other than the hope of more direct intervention from Damascus or Tehran.
However, HAMAS has now been goaded by Hizbollah into taking as recalcitrant a stand as possible. The slim glimmer of hope - championed by neighbors Jordan and Egypt - that the HAMAS government and Israel could somehow defuse the Gaza front by carrying out a massive prisoner release in exchange for soldier Shalit, now seems to be futile. The government of Israel will continue its military press on both fronts, but it is absolutely clear that the more significant front is the northern one.
As international diplomacy tries to stave off a full-scale state-to-state war, the key "controlling legal authority" will be UN Security Council Resolution 1559 (you'll then have to open the pdf file from the list). Take a moment to read it. In polite diplomatic language, it calls for the disbanding of all militias in Lebanon, and the extension of Lebanese governmental sovereignty over all Lebanese territory. The resolution is nearly 2 years old, and it is a joke. In the coming days, this toothless document will serve as the base point for all diplomatic efforts to resolve the northern conflagration, a very unlikely outcome.
It takes no powers of prognostication to predict that the upcoming weekend will be crucial for determining the trajectory of this almost-war. Of the two fronts, the chances for a deal and cease-fire are slightly better on the southern front; but only by a slim margin. What is clear is that the southern front cannot possibly lead to a state-to-state war with Syria and its 10 divisions arrayed along the Golan Heights; keep your eyes on the northern front, where the situation can flash up to an even more dangerous level in a single moment.