As the Gaza war enters a bloody new phase -- and world pressure mounts for a ceasefire -- it is becoming clear that the key to a solution is neither Hamas nor Israel, but Egypt.
Strategically placed on the southern border of Gaza, Egypt is the primary smuggling route of weapons to Hamas. Tunnels linking Egypt and Gaza have been used to provide these Islamist militants with some 80 tons of military materiel in the last six months alone.
What Cairo does about closing the tunnels will likely be the difference between war and peace.
Egypt has an interest in shutting them down. It has a peace treaty with Israel, and views Hamas -- the Palestinian wing of the Muslim Brotherhood -- as threatening to rile up Egyptian radicals. Cairo says it will not tolerate an Islamic state on its northern border.
Despite having a clear interest in doing so, the Egyptians have not done enough to stem the weapons flow into Gaza.
Egyptian sources say the effort to counter Hamas' extensive tunnel network has been hampered by the peace treaty with Israel, which limits the number of troops allowed to be deployed in the Sinai.
Regardless of the rationale, Israel will not end its military campaign until the route of Hamas' weapons shipments is shut.
If a ceasefire is to be reached, given the dynamics on the border, any meaningful step toward curbing tunnel smuggling is likely going to have to occur on Egyptian territory. This will require Israeli flexibility and a commitment from Cairo to take meaningful steps on the tunnels.
Although Cairo may be hesitant to accept additional foreign troops on its soil -- Multinational Force Observers are already in the Sinai -- some element of international forces near the Red Sea or Sinai will probably be needed to close the tunnels and seal the ceasefire deal.
Last May, a few months after Hamas destroyed the border fence allowing an estimated 700,000 Palestinians to stream into Egypt's Sinai desert, Washington gave Egypt $23 million to help shore up the border.
Maybe it wasn't enough money, or maybe Cairo doesn't really want to commit to robust action to stop the smugglers.
But if Cairo wants to end the bloodshed, Egypt must adopt a more pragmatic approach and accept an international force solution. Cairo can be the bridge to a solution, but only if it rejects the tunnels.
David Schenker is director of the Program on Arab Politics at the Washington Institute for Near East Policy.
New York Daily News