In this paper, we aim to contribute to the literature on the determinants of constitutional compliance, or the so-called de jure–de facto constitutional gap. Constitutional rules not only enable government, but they also constrain it, which is why some government actors would benefit from non-compliance. We study how personal traits of political leaders, specifically their education and their occupational and military background, affect constitutional non-compliance. These factors have been linked to various decisions of politicians, but not to their respect for the constitution. Analyzing the behavior of hundreds of political leaders over the course of two centuries, we find that military background and education are important predictors of constitutional compliance. This leads to the normative (and difficult) question of whether constitutions should set entry barriers for high political offices that take such leader characteristics into account.