Schmid Comparative Migration Studies (2020) 8:25 Closely following the open-inclusive cases, the second on the list are the openexclusive cases (29%). They have reached a peak during the 1990s (36%), while the decades before and after they make up about a fourth. As will be further demonstrated below, this has to do with the overall liberalising trajectory in citizenship policies, which led to a decrease in regimes akin to the ‘Market Model’ and to corresponding increase in regimes akin to the ‘Liberal Model’. The number of observations that feature a closed immigration regime and an exclusive citizenship regime has dropped steadily by more than 20 percentage points from 1980 to 2010. During the Cold War they were very frequent (37%), but then rapidly declined. Finally, it is striking that the classical model that dominates in the normative literature (closed immigration regime, inclusive citizenship regime) is clearly least prevalent empirically (17%). Its highest share was also during the Cold War (22%) – the decade in which this model found its classical formulation in Walzer (1983, ch. 2). Trend analysis How have immigration regimes and citizenship regimes evolved during recent decades? The previous analysis suggests that they have both liberalised. Fig. 3 shows this aggregate liberalising tendency in both IRO and CRI.3 However, after a surge of liberalisation from 1980 onwards, the trend toward more open immigration policies stops in 1996 and IRO fluctuates thereafter. Hence, the structural tendency of IRO towards greater openness – as a result of the constraints imposed by globalization – is limited. The trajectory of citizenship policies clearly shows the restrictive turn in the 2000s, which has been discussed in much of the literature (e.g. Joppke 2008). One can also detect another restrictive turn in citizenship during the 1990s. This is a novel finding. However, albeit limited, the aggregate tendency is toward greater CRI. Regarding convergence, the declining trend in the standard deviation of IRO is particularly striking. It also continues after the aggregate level of IRO stagnates and fluctuates after 1996. The convergence in CRI is very limited (Fig. 3). Thus, whereas policy variation in immigration has decreased, variation in citizenship policies has not converged significantly. Indeed, citizenship policies have diverged somewhat during the time of its backsliding after 9/11. This indicates that the ‘restrictive turn’ in civic integration requirements has increased the variation across countries (Goodman 2014b). These findings of liberalising trends and convergence in IRO but not CRI are in tune with the implications of my theoretical arguments. They also confirm previous analyses (e.g. Helbling and Kalkum 2018; Koopmans et al. 2012), while contradicting contrasting conjectures expecting greater liberalisation and convergence in CRI (e.g. Joppke 2010). However, the results also show important variation across geopolitical periods; the structural forces underpinning immigration and citizenship policies, their liberal and illiberal variants, and the interplay among them, appear to be dynamic. Correlation analysis Are immigration regimes and citizenship regimes statistically independent? The CATPCA has used an orthogonal VARIMAX rotation, which assumes a priori that the 3 The evolution of policies by country is shown in Additional file 1. Page 15 of 20