Ten years ago, Israel began work on its infamous, meandering "separation barrier" (read: giant wall), which today divides Israel proper from the West Bank. Now, they're doing it again: this time on the border with Lebanon.

The new five metre-high wall shields the Israeli town of Metulla from the neighbouring Lebanese town of Kfar Kila, hardly a football pitch away. Israeli government officials claim such walls are necessary for security, but can Cold War-style barriers really address 21st-century problems?

We've been here before...

During the second intifada, the years-long Palestinian uprising against Israeli occupation, the government of Israeli prime minister Ariel Sharon began work on a massive 700km-plus barrier to divide Israel proper from the Palestinian West Bank. A decade later the wall, which grabbed 10% of the West Bank for Israel, is still incomplete, but Israeli officials credit it with a big fall in Palestinian attacks in Israel.

Whether or not the wall is responsible for the lull in violence, Israel has chosen to extend the logic of the barrier to other trouble spots. After evacuating the last Jewish settlers from the Gaza Strip in 2005, Sharon's government effectively encircled the enclave with security barriers and no-go zones. Now new, higher walls are going up on the already fenced Lebanese border, and even on Israel's barren frontier with Egypt's Sinai desert.

Connecting these concrete and barbed wire barriers is an even more ambitious project, known as the "Iron Dome": a state-of-the-art short-range rocket interception system. Proponents hope it will protect Israel's cities against rocket fire from areas such as Gaza and southern Lebanon. Developed by an Israeli firm, and supported by hundreds of millions of US aid dollars, the Iron Dome successfully intercepted missiles fired from Gaza this March, and is expected to be deployed across the country.

New coalition, same mindset

Israel's defence projects, large and small, speak to the nation's current mentality: one of a people under siege. Thanks in large part to its own actions, Israel faces tremendous opposition from the Palestinian territory it occupies and the neighbours it has often fought. Israel's avowed enemy, Hezbollah, remains Lebanon's strongest actor; Hamas retains control of Gaza; and formerly friendly (or at least passive) regimes in Egypt and Syria have fallen, or likely will, under the weight of the Arab spring.

From southern Lebanon to the Golan Heights, the West Bank and Sinai to Gaza, the frontiers where Israel erects its walls are all areas the country has conquered and occupied or annexed. Worse still, the walls do not follow agreed borders, particularly in relation to Lebanon and the West Bank. The net result: these short-term security fixes will ensure long-term conflicts.

Now the Israeli government, led by Benjamin Netanyahu of the right-wing Likud party, has sealed a new coalition deal with the centrist party Kadima – founded by Ariel Sharon when he left Likud. The coalition has a massive majority in the Israeli parliament – and therefore little incentive to abandon the mindset that builds fences instead of bridges.

That, sadly, will only serve to isolate Israel in the region, and makes prospects of normalisation (let alone peace) even more remote. The Arab spring has brought with it tremendous turmoil, but also rare opportunity. A courageous leader would use such a time to tear down walls rather then build them up.