One argument say, opening border between countries will make threats for nationhood. They believe that without border the security in country will be under threat and there will be conflict. In addition opening border will lead to the great movement of people from poor countries and, that make more concern for development countries like USA and, European Union. This movement will make instability in rich countries.
However, opening border between countries has much benefit. Increasing globalization necessitates countries to open their border for the trade, technology, tourism, and, to have more labour. Furthermore, opening border lead toward unify economics, currencies, technology, and, securities. For example, European Union is one of the most power area in the world because, it has free zone.
In conclusion, people have always moved from place to another in order to have convenient life. Also countries should make this movement more easy because, it due a benefit to the countries from many aspects. Therefore, border between countries should be banned.