United States President Theodore Roosevelt sought to prevent European intervention, largely to protect the routes to the future Panama Canal, as the canal was already under construction. He made a small military intervention to ward off European powers, to proclaim his famous Roosevelt Corollary to the Monroe Doctrine, and also to obtain his 1905 Dominican agreement for U.S. administration of Dominican customs, which was the chief source of income for the Dominican government. A 1906 agreement provided for the arrangement to last 50 years. The United States agreed to use part of the customs proceeds to reduce the immense foreign debt of the Dominican Republic and assumed responsibility for said debt.