Watching the news of the past few weeks, one is struck by how countries which have spent much of the past 50 years espousing the concept of open borders and even a “borderless” world are reneging on that policy. The mass flow of refugees from the war-torn countries of the Middle East and the famine-ravaged countries of Africa has resulted in a reconstruction of physical borders in and around Europe which, we had been led to assume, was a geopolitical characteristic relegated to the history of 19th and 20th century nation states, but which – in an era of peace and neighborly relations – was no longer necessary.While European nations envisaged the free and unhindered cross-border movement of internal migrants from the poorer countries of the EU (such as Poland or Romania) to the wealthier states (such as the UK, Germany and Scandinavia), no one envisaged the mass movement which would take place as a result of the present ethnic and religious upheavals in the neighboring regions of the Middle East and parts of Africa.Unable to deal with this enormous human problem, and faced at home by groups opposed to immigration – especially to those groups who bring with them different cultural and religious mores, – restrictions on immigration beyond a single humanitarian quota have become tougher. Countries at the periphery of the EU have began to reconstruct the barbed wire fences and concrete walls which we were led to believe were a thing of the past.Notwithstanding, it remains that much easier to cross a border between countries today than it was in the past – and it does not appear as though the new border fences throughout Europe will have any significant long-term impact on the continued flow of refugees fleeing for their lives from the war-torn regions of their homelands.In Israel, where our borders have always been a point for national debate, and where only two (with Egypt and Jordan) have ever received full international recognition by virtue of the peace treaties which have been signed, many of the borders were left open. For well over 30 years, the border between Israel and the Egyptian Sinai peninsula was not fenced or walled in, while the border running from Eilat-Aqaba in the South to the Jordan-Israel-Syria meeting point in the North, was a flimsy, often dilapidated fence, which few on either side had any desire to cross or to stray into.Until 10 years ago, there was no significant refugee or migrant issue of people arriving in Israel via Sinai from Ethiopia, Somalia and Sudan, to seek safety or to find a better life for themselves and their families. There was a problem of smuggling along the Israel-Egypt border but this was dealt with adequately by the Border Police on both sides. The sensitivity of the political relations between the two countries, even after the signing and implementation of the Camp David Peace Accords, meant that a blind eye was often turned to this sort of activity – as too was the ongoing smuggling of goods between Israel and the West Bank along the southern portions of the region. In both cases, the border crossings were managed and negotiated through local Beduin communities, whose tribes and families straddle both sides of the border.But in Israel too, borders have returned with a vengeance. Starting 10 years ago we unilaterally constructed the separation/security barrier/fence/wall (delete whichever term you are uncomfortable with), that separated Israel from the West Bank and effectively closed the border to movement of Palestinians seeking menial labor in Israel – beyond the chosen few who were granted (at no little cost and often with the assistance of bribes and bakshish) work permits to enter and exit Israel on a daily basis. Anyone who has ever crossed any of the five major crossing points along the course of the separation barrier will know that, while Israel may be averse to calling it a political “boundary,” it functions as does any international border, with documents examined, trucks inspected for illegal goods and customs duties paid. Access to and from the neighboring regions are permitted to some and denied to many.FOLLOWING THE near completion of the separation barrier, Israel constructed a new fence along the entire length of the Israel-Egypt border, which had lain fairly open during the previous 30 years. Ostensibly built to prevent the unhindered flow of migrants from Africa, this too has become a major new security consideration as fundamentalist groups have moved into the Sinai peninsula to challenge both the Egyptian and the Israeli regimes. This border is now equipped with highly sophisticated surveillance technology and stringent border management, as Israel attempts to prevent radical groups from approaching the border, or crossing into Israel, to unleash a new round of violence and terror.And just as the government is completing the construction of the Israel-Egypt border, Prime Minister Netanyahu has announced that one of the major infrastructural projects for the next decade will be the completion of a new, fortified, border along the entire western length of the country, starting at Eilat in the South and running the entire length of the Arava and Jordan valleys. This too is seen as fulfilling a double role – preventing the flow of migrants from war-torn Syria and Iraq to the east, and enabling greater control over the movement of potential terrorists associated with Islamic State, some of whom have already taken control of areas in close proximity to Israel’s border with Syria in the Golan Heights and have approached the fence on a number of occasions.None of these borders can prevent the firing of missiles, be they from Gaza, from South Lebanon or – potentially in the future – from Syria or the Sinai peninsula – into Israel itself.The rockets and missiles currently stocked by Hezbollah and Hamas can reach almost every point in Israel. It is the Iron Dome anti-missile system, rather than the line of the border, which will prove to be the frontline against this threat. But even if the new borders are unable to prevent the firing of missiles, they are important in many other respects – in demarcating the sovereign territory of the State and in preventing the physical movement of people or goods which the State deems as undesirable or “alien.”It is somewhat ironic that Israel is now in the process of completing the fencing in of the entire country, a sort of self-ghettoization from the outside world. This is in direct contrast to the dreams of the founding fathers who saw Israel as eventually integrating into its region – if not culturally, then at least economically and politically. No longer would Jews have to sit behind walls to protect them from anti-Jewish hatred of those on the other side. No longer would a Jewish State allow others to enclose them inside walls and prevent them from moving freely into the surrounding environment.But the economic and political realities of the past decade have proved to be too strong.Borders have returned with a vengeance to Israel. Borders are collapsing in the rest of the Middle East, states are crumbling and undergoing territorial reconfiguration as part of a new Middle East, very different to the one envisaged by former president Shimon Peres. It is no longer possible to test the Israel-Egypt-Jordan peace treaties through porous borders. The new barriers, fences and walls are designed to prevent any movement from one side to the other. Such are the political realities of the region in which we live, reflecting the changing geopolitics of a world for whom borders are rapidly regaining their previous significance and importance.The writer is the Dean of the Faculty of Humanities and Social Sciences and incumbent of the Professorial Chair in Geopolitics at Ben-Gurion University of the Negev. The views expressed are his alone.