I argue that modern European philosophy served Simón Bolívar as a theoretical science positing a set of general principles for politics and the human soul. These principles were in turn translated into practical projects of two kinds. One sought the liberal ends of vanquishing despotism and arbitrary government. To secure such ends, required attention to the protection of basic rights, the balance and separation of powers, and the sovereignty of the people, all of which could be reconfigured within a constitution, but also adapted if need be to meet the circumstances at hand. The other involved knowledge of the mechanics of the human soul, the strings of passions and sentiments that a deft educator could manipulate to produce social harmony. By channeling human passions and sentiments, Bolívar sought to socialize the heterogenous inhabitants of Spanish America for republican life. He assumed that by reorienting passions and through a sentimental education that one could create new shared political opinions to unite the nascent republics of the Americas. I focus on two constitutional moments to illustrate Simón Bolívar's consistent concern for liberal institutional design and moral formation based on sentiment and passion: the Angostura constitutional proposal for Venezuela in 1819 and the initial draft of the Bolivian Constitution of 1826.