This dissertation is a study of Panamanian nationalism from 1903--31. The dissertation notes that Panamanians had long been pressing for their own country before the U.S. intervention in 1903. In reaction to Colombian neglect, the white mercantile elite of the nineteenth century had attempted to 'civilize' the Isthmus by connecting itself to an outside power. The oligarchy had hoped to build an interoceanic route and assure its social position in an Afro-mestizo society. The Panamanian nationalists thus favored the U.S. intervention although their situation remained unstable during the following years After the separation from Colombia, the Panamanian elites faced a number of problems that put into question their dominance of the country. With the construction of the canal, investment poured into Panama, and foreigners appropriated major economic sectors. Latin Americans portrayed the Isthmus as a U.S. colony while thousands of West Indians immigrated to work on the canal. Meanwhile the popular classes began to organize and enter political life. The oligarchy was losing control over society while imperialism proved equally troublesome to the new middle class. This group was itself the product of modernization and had often studied abroad or at the new Instituto Nacional. Eager to take up leadership, they were blocked by the North American advisors who tended to dominate the government In response, middle and upper class intellectuals reformulated Panamanian nationalism to protect their interests and threatened stature. On the one hand, they renewed efforts to 'civilize' the Isthmus as their education and the country's traditions dictated the continuation of these themes. However, new ideas emerged at the same time. Writers and artists now gave importance to Hispanidad, to legitimize the republic in eyes of its Latin American neighbors and to force the immigrant populations to accept traditional leadership. The Panamanians did not resort to the tactic of populism, because the masses were increasingly foreigners and were jeopardizing their social status. Instead intellectuals and political leaders protected their position by ignoring the ethnic complexity of Panamanian society. Panamanian nationalism became an exclusionary nationalism and would reach a highpoint during the presidency of Arnulfo Arias Madrid (1939--41)