“Nothing is so striking today, nothing has such decisive importance for the whole shape of today’s social and political life, as the yawning contradiction between an economic foundation that grows tighter and firmer every day, binding all nations and countries into a great whole, and the political superstructure of states, which seeks to split nations artificially, by way of border posts, tariff barriers and militarism, into so many foreign and hostile divisions” (Rosa Luxemburg, Introduction to Political Economy, in The Complete Works of Rosa Luxemburg, Volume 1, Verso, London 2013, p 121)
Borders as a demarcation of the ownership of land are as old as the existence of property itself. There simply is no existence of property without the demarcation and defence of it. With the advent of major empires such as the Rome or China, gigantic fortified borders were set up: Hadrian’s Wall, Limes, the Great Wall of China. So the existence of such borders to defend an empire against the invasion of rivals is nothing new.
However, as long as the planet was not yet “divided” amongst the major capitalist rivals, the demarcation of borders still remained mostly at low levels or could even be settled at the negotiation table through treaties. For example in 1884 at the Berlin Conference, borders in Africa could still be drawn on a map; in the early 19th century a territory as big as Alaska was sold by the Russian Czar to the USA. At the turn of the 19th century the Mexican-US border almost had no guards. And at the time of World War One, borders in Europe still were not heavily guarded.
Only once the world had been divided amongst the major capitalist rivals at the turn of the 20th century did the defence of territories become a battle on a different scale. But even though WW1 contained large battles for territories – such as the trench war in Belgium and France, with their terrible cost in human lives and material - the borders remained remarkably ‘open’ after the war. The reparations imposed on the defeated countries by the Versailles Treaty were either a relatively minor loss of territory (the German Saarland, ‘lost’ to France, or the former German colonies, which changed owners) or were made up of big financial payments. However, there was not yet any partition of entire countries, and there were not yet any fortifications of borders as would occur after World War Two.
With the intensification of imperialist rivalries, the defence of borders and territories has changed qualitatively. A fierce fight over every inch of territory set in. After WW 2 a number of countries were divided (Germany, Korea, China, Vietnam, India-Pakistan), all of which set up the most militarised borders, equipped with mines, fences, walls, armed guards and dogs. The formation of the state of Israel in 1948 meant the displacement of hundreds of thousands of Palestinians and the need to entrench itself behind the most sophisticated walls. This has now led to one of the most heavily guarded border walls in the world. “Symbolically, the wall in Palestine is this century’s Berlin Wall, albeit four times as long as that hated Cold War icon and more than twice as high – 8 m.. Under construction since 2002, it is expected to eventually extend for 709 kilometres through the West Bank. A series of concrete slabs, barbed-wire ‘buffer zones’, trenches, electrified fences, watchtowers, thermal-imaging video cameras, sniper towers, military checkpoints and roads for patrol vehicles have dismembered the cities of the West Bank and segregated them from occupied East Jerusalem (…) The wall has cost over $2.6 billion so far, while the cost of yearly maintenance is $260 million”.
In sum: since WW1 all countries are imperialist and have to obey the law of defending their interests also through the most obnoxious border defence systems.
And the recent series of wars across the planet has meant that frontiers have been fortified to prevent the infiltration of enemy forces- often terrorist gangs with various states behind them.
A whole system has been set up to screen any person in need of a visa, and Orwellian surveillance institutions like the Homeland Security Authority in the US have been developed to track down possible enemies and prevent them from entering the country.
At the same time while migration in the 19th century was not so much hampered by a complex legislation and a sophisticated police system, the 20th century meant that the borders have now also taken on a second function in addition to the ‘traditional’ military one: to prevent the entrance of labour power that is not needed. Contrast this with the USA’s demand for labour at the end of the 19th century – the real reason for the appeal to “send us your poor, your huddled masses”. Today the USA has joined the race to seal off its southern borders against waves of Latin American proletarians in flight from poverty and criminality in Central and South America.
In the 1960s another new phenomenon appeared. Many of the countries dominated by the Russian bloc had a shortage of labour, in particular East Germany. Thus the East German State erected the Berlin Wall which had to prevent its work force from leaving its territory. The economic underdog closed its borders to keep its citizens inside.
So now more and more we have a simultaneity or double function of borders: in addition to the classical military function of defence of territory, the most sophisticated walls are constructed to prevent refugees from entering and preventing or filtering unwanted “economic migrants”.
So although the Iron Curtain collapsed in 1989, the disappearance of the confrontation between the old blocs did not mean a new borderless world. On the contrary!
“Between 1947-1991 eleven walls were built, which survived the end of Cold War (South-Africa-Mozambique, Zimbabwe, North-South Korea, India-Pakistan, Israel, Morocco-West-Sahara, Zimbabwe-Zambia). Between 1991-2001 seven walls were erected: Around the exclaves Ceuta, Melilla, USA-Mexico, Malaysia-Thailand, Kuweit-Iraq, Uzbekistan-Afghanistan/Kirgizistan). 22 walls were erected since 2001: Saudi-Arabia-United-Arab Emirates, Iraq, Oman, Qatar, Yemen, Burma-Bangladesh, Botswana-Zimbabwe, Brunei-Malaysia, China-North-Korea, Egypt-Gaza-strip- United Arab Emirates-Oman, India-Bangladesh, Burma-Pakistan, Iran-Pakistan, Israel-Jordan/West-Bank, Jordan-Iraq, Kazakstan-Uzbekistan, Pakistan-Afghanistan, Thailand-Malaysia- Turkmenistan-Uzbekistan, Israel-Egypt.
(www.dandurand.uqam.ca/evenements/evenements-passes/440-fences-and-walls-... also Chaire Raoul-Dandurand _ Fences and Walls in International Relations.html, Berlin Wall is Gone but Separation Walls are a Growth Industry _ Burning Billboard.org.htm)
Between the almost 200 countries of the world there are some 250,000 kilometers of borders. An entrenched society!
This shows the totally irrational character of the capitalist system. While capitalism can only ‘prosper’ if there is free mobility of goods and labour, the movement of human labour is submitted to the most ruthless checks and obstacles. This means not only an unknown level of violence along the borders, but also totally lunatic financial costs. The massive border protection system between Mexico and the US costs a fortune: “But that has come at a cost. Most estimate inspection, patrol, and infrastructure set taxpayers back somewhere between $12 billion and $18 billion per year. That's up about 50% from the early 2000s, according to the Journal, which says spending has included ‘everything from 650 miles of fencing to military aircraft, marine vessels, drones, surveillance equipment, infrared camera towers and detention centres’. More generally, border security costs totalled $90 billion between 2002 and 2011, a Freedom of Information Act request conducted by the Associated Press shows. The news outlet reports that annual expenses vary from drug-sniffing dogs -- $4,500 each -- to National Guard troops -- about $91,000 per soldier”. (Source https://www.fool.com/investing/general/2014/08/06/the-migrant-crisis-could-cost-billions-but-border.aspx)
If you imagine the total number of guards all along the borders in the world, their cost would be the most absurd figure – and it shows graphically what this society wastes its resources on! 
We should add that, along with the most sophisticated border controls, within each country more and more “gated communities” are set up, fences and often armed protection systems for the privileged. Entire neighbourhoods have become “no-go-areas” for non-residents.
But the industrial countries are not only becoming real “bunkers”. They are also the biggest “deporters” of labour-power. While the total number of slaves who were taken by force mainly from the African continent amounts to some 10-20 million during period 1445-1850, the deportation policy by the industrialised countries and even other states will probably reach a similar number in a much shorter span of time. A few examples: more than 5 million ‘illegal’ immigrants have been deported from the US - under G.W. Bush around 2 million, under Clinton almost 900,000, and under Obama more than 2 million. In Europe the measures are tougher and tougher, and there about 400 detention centres for ‘illegals’ awaiting deportation. Mexico itself deports 250,000 foreigners a year to Central America. Saudi Arabia is to deport more than one million people who live and work illegally in the kingdom.
Faced with the recent wave of refugees from the war torn areas of the Middle East, Afghanistan, Northern Africa... the system of border protection has reached a new scale. The authorities deploy ever more troops and material to detain and deport refugees. More than a quarter of a century after the “opening” of the Iron Curtain in Hungary, Hungary has sealed its border with Serbia with barbed wire to prevent “Les misérables” from reaching “safer havens”, and it is planning to set up another Iron Curtain along the Romanian border. Similar measures are being taken in other European countries. The previously “open” Schengen borders are now controlled by border police; “hotspots” (refugee ‘selection’ centres are to be set up in Greece and Italy, with the possibility of sending back refugees to the inferno where they came from. Or outposts for holding back refugees are extended to Africa itself, where arrangements are made to set up border controls at the refugee transit routes in Africa.
The pictures of refugee treks and thousands of detained or repulsed refugees on the Balkans and elsewhere, left without food and shelter, remind us of the way the Jewish population was treated under the Nazi regime or the fate of the refugees at the end of World War Two. They show the continuity of barbarism in this system. A century of war refugees, of camps, of deportations, of Iron Curtains, of illegal migration and deportation of those who have the cheek to come only to fill their bellies.
We now have the highest and longest walls ever to prevent war refugees and desperate ‘economic’ migrants from entering – but they still cannot stem the tide of victims of the combined effects of capitalism’s inexorable decomposition.
By creating a global economy, capitalism has created the conditions for a world wide human association. But its total inability to realise it is illustrated today by the universal fortification of its frontiers. Calls for ‘no borders’ by well-meaning activist groups are thus entirely utopian. Borders can only be abolished through international proletarian revolution, which will dismantle the anti-human prison of the nation state.
 Worldwide 500,000 tonnes of barbed wire are produced every year. This is good for 8 million km of barbed wire, i.e. 200 times the circumference of the earth.
 And the amount of money refugees have to pay to human traffickers has also reached unheard of proportions.