Over the past three decades, the populist radical right (PRR) has experienced electoral success across the Western world, particularly in rural, peripheral or former industrial regions. This unequal geography of support has fuelled the 'left-behind' narrative, which posits that regional economic decline drives support for the PRR. Strongly articulated after Brexit, this narrative has gained traction to explain the rise of populism across Western Europe and beyond. This paper tests this narrative by analyzing four pivotal votes, where the PRR achieved breakthrough success: the 2016 Brexit referendum, the 2016 election of Donald Trump, the 2017 French presidential election, and the 2022 success of Giorgia Meloni’s Fratelli d’Italia. Our analysis distinguishes electoral units at a detailed geographical level and assesses how regional economic decline, measured by changes in median income, depopulation and labour market decline, correlates with PRR voting patterns. Unlike previous studies aggregating several countries into a single analysis, we estimate separate models for each country, revealing considerable heterogeneity. Our findings indicate that the left-behind narrative explains voting patterns well for Brexit and for Le Pen in France. However, it works less well in the US, where Trump’s highest support came from poor but economically catching up counties. In Italy, the narrative fails completely, with the PRR thriving in wealthy and economically improving provinces. These findings caution against extrapolating the left-behind narrative across different national contexts. The relationship between regional economic conditions and populist radical right support is more complex than often assumed and shaped by unique national histories.