In the end, the union (called United States of Colombia 1863–1886 and the Republic of Colombia since 1886) was made possible by the active participation of USA under the 1846 Mallarino–Bidlack Treaty until 1903. In the 1840s, two decades after the Monroe Doctrine declared US intentions to be the dominant anti-European imperial power in the Western Hemisphere, North American and French interests became excited about the prospects of constructing railroads and/or canals through Central America to quicken trans-oceanic travel. At the same time, it was clear that New Granada's control over the isthmus was becoming untenable. In 1846, the US and New Granada signed the Mallarino–Bidlack Treaty, granting the US right of way across the Isthmus, and most significantly the power to intervene militarily, ensuring neutrality of the Isthmus, and guaranteeing New Granada sovereignty.Musicant, I, The Banana Wars, 1990, New York: Macmillan Publishing Co.,
In the end, the union (called United States of Colombia 1863–1886 and the Republic of Colombia since 1886) was made possible by the active participation of USA under the 1846 Mallarino–Bidlack Treaty until 1903. In the 1840s, two decades after the Monroe Doctrine declared US intentions to be the dominant anti-European imperial power in the Western Hemisphere, North American and Frenc,h interests became excited about the prospects of constructing railroads and/or canals through Central America to quicken trans-oceanic travel. At the same time it was clear that New Granada's control over the isthmus was becoming untenable. In 1846, the US and New Granada signed the Mallarino–Bidlack Treaty, granting the US right of way across the Isthmus, and most significantly the power to intervene militarily, ensuring neutrality of the Isthmus, and guaranteeing New Granada sovereig,nty.Musicant, I, The Banana Wars, 1990 New York: Macmillan Publishing Co.,