This paper explores temporal variation in partisan effects on social spending growth in OECD countries over the period 1971–2002. We argue that partisan effects are jointly conditioned by globalization and the mobilizational capacity of organized labour. We present three main empirical findings. First, we show that partisan effects increased from the mid-1970s to the late 1980s and then dis- appeared in the 1990s. Second, we show that partisan effects rose with globaliza- tion in the 1970s and early 1980s, a period characterized by rising labour strength in many OECD countries, but this is not true for the post-1990 period, characterized by declining labour strength. Third, we show that globalization was associated with declining partisan effects in countries that experienced union decline in the 1980s and 1990s, but it was associated with rising partisan effects in countries in which unions remained strong.