Walls are not perfect, but they do work. Just ask the Chinese who fought off invading hordes from Mongolia, or the Romans who walled IN the “barbaric” Scots (Hadrian’s Wall), or more recently the Israelis who saw a massive reduction in Palestinian incursions once their wall was finished.
Spain has two enclaves in Morocco, and during the late 90s Spain had to strengthen the walls separating its borders from Morocco in Ceuta and Melilla as illegal immigration had increased. But 3-metre fencing was not enough, so about 10 years later they created a double barbed wire fence to try and reduce immigration numbers.
Despite this, numbers have kept increasing and have now reached a record – in 2017, 27,000 illegal immigrants came across the Southern border into Spain, triple the number in 2011 and almost double the number in 2016.
Turkey for example has negotiated with The EU to keep its entrance route under control, although recent stories have indicated that is now failing. Likewise, Spain and Morocco have a delicate balance to maintain, which in the past was helped immensely by the ex-King of Spain Juan Carlos’s good relationship with the Kings of Morocco. That relationship is not as effective now under King Philip of Spain.
Therefore, there are constant mass attacks (1000+ men) on the “walls” in Ceuta and Melilla by sea and by land, with some dying in the attempt to cross. As Trump tries to build his Southern Wall, Spain is trying to fix its Southern immigration problem with faster deportation agreements with Morocco.
Border systems work only when strictly enforced. Defending a nation’s civilians and its civilisation is their primary purpose. Europe would do well to remember that.