The late 19th century, and more precisely the period between the Irish Famine of 1845-49 and the First World War, was an era of largely free migration. As such, it constitutes a unique policy experiment, in which migration flows reflected underlying economic forces, rather than government policy. Moreover, since there was large-scale migration between relatively rich countries with relatively well-developed states, and since the migration was legal, it was extremely well-documented. There are three big lessons from the late 19th century. First, emigration is an incredibly effective way for poor countries to raise their living standards. By blocking immigration, rich countries are making it much harder for poor countries to catch up on the OECD. Second, emigration is ultimately a self-limiting process. Left to its own devices, emigration from a poor country will eventually decline, although this may be preceded by an initial period of increasing emigration rates. Third, international migration can have big effects on internal income distribution, both in the source country and in the country of origin; and this leads to strong pressure for immigration restrictions. This last, pessimistic, conclusion ignores the possibility, however, that domestic and foreign institutions could help governments maintain relatively open migration policies.
