Panama is a transcontinental country spanning the southern part of North America and the northern part of South America.

Prelude to 1904 Explored and settled by the Spanish in the 16th century, Panama broke from the Spanish Empire in 1821. Shortly after declaring independence from Spain, it chose to exist as the Department of the Isthmus within the Republic of Gran Colombia, which had been created in 1819 as a union of Nueva Granada with the precursor of today's Ecuador and with the precursor of today's Venezuela. Over the next 90 years, political differences between supporters of federalism and centralism, as well as regional tensions and the occasional civil war, would steadily change the geo-political landscape of the region. Gran Colombia dissolved in 1831, with Panama and Nueva Granada choosing to remain joined, as the Republic of New Granada. This smaller republic was transformed in 1858 to the Granadine Confederation, thru a constitutional change that decentralized more aspects of governance, giving Panama (and the other constituent states) more control of their regions. The Granadine Confederation was replaced by the United States of Colombia, through another constitutional change in 1863, further decentralizing governance to nine "sovereign states”. In 1886, following further internal conflicts, the United States of Colombia was replaced by the more centralist Republic of Colombia. On 3 November 1903, following a series of disagreements between Panamanian groups and the Senate of the Republic regarding efforts to construct a canal, the separation of Panama from Colombia took place, with Panama declaring itself the Republic of Panama. On 18 November 1903, the Hay–Bunau-Varilla Treaty, regarding the canal, was signed by Panama and the United States.

Organizing the new republic The provisional governing junta, selected when independence was declared, governed the new state until a constitution was adopted in 1904. Under its terms, Manuel Amador Guerrero became Panama's first president.

The constitution was modeled, for the most part, after that of the United States, calling for separation of powers and direct elections for the presidency and the legislature, the National Assembly. The assembly, however, elected three persons to stand in the line of succession to the presidency. This provision remained in effect until 1946, when a new constitution provided for direct election of the vice president. The new republic was unitary; municipalities were to elect their own officials, but provincial authorities were to be appointed by the central government. The most controversial provision of the constitution was that which gave the United States the right to intervene to guarantee Panamanian sovereignty and to preserve order.

A two-party system of Liberals and Conservatives was inherited from Colombia, but the party labels had even less precise or ideological meaning in Panama than they had in the larger country. By the early 1920s, most of the Conservative leaders of the independence generation had died without leaving political heirs. Thus, cleavages in the Liberal Party led to a new system of personalistic parties in shifting coalitions, none of which enjoyed a mass base. Politics remained the exclusive preserve of the oligarchy, which tended to be composed of a few wealthy, white families.

Having successfully severed their ties with Colombia, the secessionists of Panama's central government were soon faced with a secessionist problem of their own. The Guna of the San Blas Islands were unwilling to accept the authority of Panama, just as they had been unwilling to accept the authority of Colombia or Spain. The Panamanian government exercised no administrative control over the islands until 1915, when a departmental government was established; its main office was in El Porvenir. At that time, forces of the Colonial Police, composed of blacks, were stationed on several islands. Their presence, along with a number of other factors, led to a revolt in 1925.

In 1903 on the island of Narganá, Charlie Robinson was elected chief. Having spent many years on a West Indian ship, he began a "civilizing" program. His cause was later taken up by a number of young men who had been educated in the cities on the mainland. These Young Turks advocated forcibly removing nose rings, substituting dresses for molas, and establishing dance halls like those in the cities. They were actively supported by the police, who arrested men who did not send their daughters to the dance hall; the police also allegedly raped some of the Indian women. By 1925 hatred for these modernizers and for the police was intense throughout the San Blas Islands.

The situation was further complicated by the factionalism that resulted when Panama separated from Colombia. The leader of one of these factions, Simral Coleman, with the help of a sympathetic American explorer, Richard Marsh, drew up a "declaration of independence" for the Guna, and on February 25, 1925, the rebellion was underway. During the course of the rebellion, about twenty members of the police were killed. A few days later a United States cruiser appeared; with United States diplomatic and naval officials serving as intermediaries, a peace treaty was concluded. The most important outcome of this rebellion against Panama was a treaty that in effect recognized San Blas as a semiautonomous territory.

United States intervention and strained relations In the very first year of the Hay-Bunau-Varilla Treaty, dissension had already arisen over the sovereignty issue. Acting on an understanding of its rights, the United States had applied special regulations to maritime traffic at the ports of entry to the canal and had established its own customs, tariffs, and postal services in the zone. These measures were opposed by the Panamanian government.

Mounting friction finally led Roosevelt to dispatch Secretary of War William Howard Taft to Panama in November 1904. His visit resulted in a compromise agreement, whereby the United States retained control of the ports of Ancón and Cristóbal, but their facilities might be used by any ships entering Panama City and Colón. The agreement also involved a reciprocal reduction of tariffs and the free passage of persons and goods from the Canal Zone into the republic. Compromises were reached in other areas, and both sides emerged with most of their grievances blunted if not wholly resolved.

Before the first year of independence had passed, the intervention issue also complicated relations. Threats to constitutional government in the republic by a Panamanian military leader, General Esteban Huertas, had resulted, at the suggestion of the United States diplomatic mission, in disbanding the Panamanian army in 1904. The army was replaced by the National Police, whose mission was to carry out ordinary police work. By 1920 the United States had intervened four times in the civil life of the republic. These interventions involved little military conflict and were, with one exception, at the request of one Panamanian faction or another.

The internal dynamics of Panamanian politics encouraged appeals to the United States by any currently disgruntled faction for intervention to secure its allegedly infringed rights. United States diplomatic personnel in Panama also served as advisers to Panamanian officials, a policy resented by nationalists. In 1921 the issue of intervention was formally raised by the republic's government. When asked for a definitive, written interpretation of the pertinent treaty clauses, Secretary of State Charles Evans Hughes pointed to inherent difficulties and explained that the main objectives of the United States were to act against any threat to the Canal Zone or the lives and holdings of non-Panamanians in the two major cities.

Actual intervention took several forms. United States officials supervised elections at the request of incumbent governments. To protect lives of United States citizens and property in Chiriquí Province, an occupation force was stationed there for two years over the protests of Panamanians who contended that the right of occupation could apply only to the two major cities. United States involvement in the 1925 rent riots in Panama City was also widely resented. After violent disturbances during October, and at the request of the Panamanian government, 600 troops with fixed bayonets dispersed mobs threatening to seize the city.

At the end of the 1920s, traditional United States policy toward intervention was revised. In 1928 Secretary of State Frank B. Kellogg reiterated his government's refusal to countenance illegal changes of government. In the same year, however, Washington declined to intervene during the national elections that placed Florencio H. Arosemena in office. The Arosemena government was noted for its corruption. But when a coup d'état was undertaken to unseat Arosemena, the United States once again declined to intervene. Though no official pronouncement of a shift in policy had been made, the 1931 coup d'état—the first successful one in the republic's history—marked a watershed in the history of United States intervention.

Meanwhile, popular sentiment on both sides calling for revisions to the treaty had resulted in the Kellogg-Alfaro Treaty of 1925. The United States in this instrument agreed to restrictions on private commercial operations in the Canal Zone and also agreed to a tightening of the regulations pertaining to the official commissaries. At the same time, however, the United States gained several concessions involving security. Panama agreed to automatic participation in any war involving the United States and to United States supervision and control of military operations within the republic. These and other clauses aroused strong opposition and, amid considerable tumult, the National Assembly on January 26, 1927, refused to consider the draft treaty.

The abortive Kellogg-Alfaro Treaty involved the two countries in a critical incident with the League of Nations. During the fall of 1927, the League Assembly insisted that Panama could not legally participate in the proposed arrangement with the United States. The assembly argued that an automatic declaration of war would violate Panama's obligations under the League Covenant to wait three months for an arbitral decision on any dispute before resorting to war. The discussion was largely academic inasmuch as the treaty had already been effectively rejected, but Panama proposed that the dispute over sovereignty in the Canal Zone be submitted to international arbitration. The United States denied that any issue needed arbitration.

A new accommodation In the late 1920s, United States policymakers noted that nationalist aspirations in Latin America were not producing desired results. United States occupation of Nicaragua, Haiti, and the Dominican Republic had not spawned exemplary political systems, nor had widespread intervention resulted in a receptive attitude toward United States trade and investments. As the subversive activities of Latin American Nazi and Fascist sympathizers gained momentum in the 1930s, the United States became concerned about the need for hemispheric solidarity.

The gradual reversal of United States policy was heralded in 1928 when the Clark Memorandum was issued, formally disavowing the Roosevelt Corollary to the Monroe Doctrine. In his inaugural address in 1933, President Franklin D. Roosevelt enunciated the Good Neighbor Policy. That same year, at the Seventh Inter-American Conference in Montevideo, the United States expressed a qualified acceptance of the principle of nonintervention; in 1936 the United States approved this principle without reservation.