How has the emergence and transformation of welfare states influenced immigration policies? Assuming that there is a trade-off between social rights and openness, has the expansion of welfare states over time led to a greater need for governments to control access via immigration control or restrictions on migrant rights? The transition from minimal state and open borders in the period 1870-1914 to the take-off in social spending and restrictive immigration policy in the period that followed points in this direction. However, can the causal link between these two policy domains be proven empirically? In this talk given at the LIMS seminar at Leiden University on March 14, 2018, I present some data and hypotheses on this connection.