Although substantial advances have been made in our comprehension of functional politicization – political capacities and activities being taken on by bureaucrats in their administrative duties – questions surrounding its causal mechanisms remain. To shed light on these questions, we here explore increasing political polarization (and fragmentation) in Dutch politics and functional politicization over the period 2007 – 2019 to see how the two are related. To do so, we adopt a cross-time approach that observes which skills – political-strategic insight, substantive expertise (