In American politics, the immigration question looms large and has tremendous power over the shape of a debate or the fate of a candidate. But migration issues are hardly a uniquely American concern — the spread of instantaneous communications has made people more aware of the relative disparities between rich and poor countries.If anything, the pace of international migration is only set to further increase in the 21st century.The long-term trends towards urbanization are a part of the same phenomenon. As communications and transportation have become less expensive and more ubiquitous, more people are leaving the farms and headed into the cities. Once in the cities of their home countries, they are ready to look farther afield.In short, look for border security and border issues to play a major role in politics for a long time to come, and not just in the US. From the middle of the 19th century, an improving travel infrastructure unlocked the doors of mass migration; the 21st century will likely be the century of migration par excellence — both within and between countries.The politics of borders will loom large.