The world appears to be moving into a new era of international migration during which gaps between policies needed to manage migratory flows and those enacted in practice will widen. Whereas immigrants in the late 20th century were motivated by a desire to improve their wellbeing by accessing opportunities in richer countries, in the early 21st century they are increasingly motivated by a desire to escape threats at places of origin, yielding very different patterns of migration and selectivity. Using the United States as an example, this paper reviews how mismatches between the underlying realities of international migration and the policies adopted to manage them, in both eras have produced and continue to produce dysfunctional outcomes. Although deleterious policy outcomes might be avoided in the future by combining a well-grounded conceptual understanding of the forces producing immigration with a clear statement of the goals to be achieved through specific policy interventions, the avoidance of further dysfunctional outcomes is unlikely to be achieved in an age of rising populism, disinformation, and xenophobia.