 According to one estimate, the period witnessed forty administrations of the Panamanian department, fifty riots and rebellions, five attempted secessions, and thirteen interventions by the United States, acting under the provisions of the Bidlack-Mallarino Treaty.Partisan clashes and foreign intervention exacerbated racial antagonisms and economic problems and intensified grievances against the central government of Colombia.Between 1863 and 1886, the isthmus had twenty-six presidents.