The Israeli wall works just fine:
What is the Israeli basis for building their wall?
Some are not walls at all, just fence.
How many are these are for anti-immigration?
How many are because of religious wars?
How many are because of race wars?
India and Pakistan - fence - threatening each other with nuclear war.
Georgia and South Ossetia - fence - should we be like the Russians?
Gaza Strip and Israel - Tensions are high there.
Israel and West Bank - Tensions are high there.
North Korea and South Korea - fence - Great Example there

European Union - just a fence - looks like most fences
Spain and Morocco - ?
Cyprus - another middle east fiasco
Morocco and Western Sahara - sand wall - bulldozed sand dunes
Ireland - separate Catholic and Protestant communities. Currently, there are 99 barriers in Belfast alone, as well as similar walls in the city of Derry. YEAH, let us follow this great example.