As Israel faces off with Hamas, it is clear that the militia is stronger this time than it was during the last Gaza War in the winter of 2008-09.
For the first time, Hamas is using missiles capable of reaching Tel Aviv and Jerusalem. Several have landed on Tel Aviv's outkirts or in the nearby Mediterranean Sea. On November 16, a missile was fired at Jerusalem, also landing on the outskirts of the city. The Iranian-made Fajr-5 missiles are much longer-range than any missiles previously in the Hamas arsenal.
At the same time, Hamas reportedly has acquired large stockpiles of weapons that could be used in ground fighting if the war escalated to an Israeli invasion of the Gaza Strip.
Many of the weapons are believed to have come to Hamas during the recent periods of chaos in Egypt and Libya that accompanied the Arab Spring.
'More Sophisticated Weapons'
Yossi Mekelman, a regional expert at London-based Chatham House, says the Fajr-5 missiles were smuggled from Iran to Gaza through Egypt's Sinai Peninsula.
"The assumption is that they arrived through the Sinai Peninsula through the tunnels [to Gaza] because since the end of the Mubarak regime the border [between Egypt and the Gaza Strip] at Rafah is quite open," Mekelman says. "And if you remember, Israel two weeks ago attacked an arms factory in Sudan. So the alleged route goes from Iran to Sudan into the Sinai Peninsula, and the lawlessness in the Sinai enables the smuggling of more and more sophisticated weapons."
Cairo's lack of control in the Sinai is a big change from the era of former President Hosni Mubarak, whose regime cooperated with Israel to control the border crossings with Gaza. The new Egyptian regime, led by Egypt's first Islamist president, Muhammad Morsi, has proven unable or unwilling to exercise the same degree of control.
Mekelman says the smuggling routes through Egypt also brought Hamas large amounts of weapons from Libya following the toppling of former strongman Muammar Qaddafi.
"Weapons during the civil war, or the revolution in Libya, disappeared. And this kind of chaotic situation creates opportunities for those who basically steal or take over ammunition and weapon storage depots and sell them for premium prices," he says.
Costly To Continue
Some analysts think that Hamas seized upon these opportunities to get new weapons as part of a larger strategy to remodel its fighting capabilities along the lines of Hizballah in Lebanon.
The Lebanese militia successfully resisted an Israeli campaign to dislodge it in southern Lebanon in 2006 through a combination of missile counterattacks and ground resistance that made it costly for Israel to continue.
Israelis take cover in a bomb shelter in central Tel Aviv as sirens wail on November 16.
Khaled Hroub, author of several books on Hamas and a professor at Cambridge University in England, says that Hamas has also adopted Hizballah's strategy of creating extensive tunnel networks that have allowed the militia to survive Israeli bombardments and to emerge from unexpected locations to fight skirmishes.
The question now for Israel is how to deal with this stronger enemy.
Israel has built a missile shield in recent years it calls the Iron Dome. It also is using air strikes to hit Hamas headquarters and communication centers and target key Hamas figures. On November 14, Israel assassinated Hamas' military chief Ahmed Jabari with a missile strike on his car.
But if the air strikes do not persuade Hamas to stop its missile attacks, the only way to suppress them would be a ground operation into Gaza. Israel has mobilized 16,000 reservists and massed tanks at the Gaza border in preparation for such an operation if necessary.
'Not An Easy Operation'
Riad Kahwaji of the Institute for Near East and Gulf Military Analysis (Inegma), a Beirut-based think tank, says Hamas now has "substantial military capabilities for an asymmetric confrontation" that could deter Israel from invading.
"From the Hamas retaliation [so far], it has become apparent that Hamas has a substantial missile arsenal of various calibers," Kahwaji says. "So it will not be an easy operation for the Israelis."
He notes that Israel not only has to weigh potential military casualties but also civilian casualties on both sides and international reaction to the death toll. During the Gaza War of 2008-09, which the Israelis called Operation Cast Lead, 13 Israelis and more than 1,400 Palestinians died.
Some analysts expect Israel to invade the Gaza Strip only as a last resort.
Natan Sachs, a regional expert at the Brookings Institution in Washington, says Israel hopes instead to convince Hamas leaders through air strikes that continuing the conflict can be too costly for them personally to continue. The assassination of Jabari is an example of that strategy.
But so far, the assassination of the top Hamas military leader appears only to have raised the stakes higher for both sides. Hamas says the killing has "opened the gates of hell" for Israel, while Israel has warned of a "significant widening" of the Gaza operation.