How did the "big stick diplomacy", "the dollar diplomacy", and "the moral diplomacy" influence the American foreign policy process of the early XXth century?

First of all it's important to contrast the ideas and strategies of Theodore Roosevelt, William Taft and Woodrow Wilson; and how they were important in the development of the American Foreign Policy during the first twenty years of the XX century.

THEODORE ROOSEVELT 

He was the President of the United States between 1901 and 1909. During the time he was in the power, he wanted to increase the influence and prestige  of the U.S on the world stage and make the country a global power. His diplomacy was based on the idea of "speak softly and carry a big stick" mantaining the idea that force, if necessary, should be used for persuassion reasons. He ended the isolationism that dominated the country and acted aggressively on foreign affairs, even without the support of the Congress. 

There were many key points which characterized Roosevelt's Big Stick Diplomacy. 

• The Phillipines: The U.S established a colonial government and Willian Taft was its governor. He established a civil government with an elected legislative assembly. 

• The Panama Canal: in 1903 the Hay-Bunau-Varilla Treaty gave the United States perpetual control of the Canal for a price of $10 million and an annual payment of $250.000. The U.S also agreed to gurantee the independence of Panama. They established a military base for their control of Central America.  

• The Roosevelt Corollary to the Monroe Doctrine: This policy was a way to approach Latin America and the Caribbean. It stated that the United States would intervene as a last resort to ensure that other nations in the Western Hemisphere fulfilled their obligations to international creditors, and didn't violate  the right of the U.S. As the corollary worked out in practice, the United States increasingly used military force to restore internal stability to nations in the region. The corollary was the perfect justification for U.S intervention in Cuba, Nicaragua and the Dominican Republic. 

• Peacemaking: In 1905 Roosevelt led negotiations to end a war between Japan and Russia, resulting in his being awarded the Nobel Peace Prize. A year later he handled a similarly explosive colonial conflict between France and Germany over the domination of Morocco.
• Great White fleet: Roosevelt sought to strengthen the U.S Navy and solidify previous gains in the Pacific. He went around the world showing the power of the U.S Navy. 

WILLIAM HOWARD TAFT 

He was the President of the United States from 1909 to 1913. He continued the Roosevelt's strategy. He generally aimed at protecting American corporate interests around the globe, Taft called his policy "Dollar Diplomacy". He wanted to expand U.S foreign trade, encouraging investments in South and Central America, the Caribbean and the Far East. It was the first way of globalization. 

With his Dollar Diplomacy, Taft started to use government officials to promote the sale of American goods overseas such as industrial goods and military hardware. He thought the U.S military would be a great tool for diplomacy. He also invited the U.S banks to rescue Honduras from hard foreign debt through the use of loans and grants. At the same time, he sent marines to stabilize Nicaragua and avoid it from falling into the hand of rebels forces. 

In spite of successes, the Dollar Diplomacy failed to counteract economic instability and the tide of revolution in places like Mexico, Dominican Republic, Nicaragua and China.

WOODROW WILSON 

Wilson was the President from 1913 to 1921. His foreign policy was based on moral principles rather than commercial or military ones.
During his government a lot of things were happening around the world. First of all the Mexican revolutionary war was happening, Wilson rejected the revolutioanry government of Victoriano Huerta and encourages anti-Huerta forces in Northern Merxico. The United States occupies the Mexican port of Veracrus and engages in confrontation against Merxican forces (Carranza's army).
Besides that, in 1914 the Word War I exploded in Europe. At first, Wilson took a neutrality stance as he opposes the nationalist campaign of the European nations at the time. "Neutral Duties" were supporting the Allies as America was selling products to Britain and France. The President supported the sale of arms to warring nations of the WEst, which enraged the Germans. In 1915 a German U-boat destroyed a Vritish liner killing more than 100 americans. That made the US enter the war to support the Allies against the Central Powers.
When the war finished in 1918 with the victory of the Allies, Wilson wrote fourteen points, which were the most important contribution to the idea of moral diplomacy as he expected to revolutionize international relations at the peace table. The fourteen points were mentioned at U.S Congress in 1918 which included general disarmament after the war, fair treatment of Russia, freedom of seas, free trade, and the creation of the League of Nations for all democratic States. In spite of it, the Congress chose not to allow American membership in the League by refusing to ratify the Treaty of Versailles. For that reason the League of Nations failed. 

At the end of the XIX century, the United States acquired overseas colonies in the Caribbean and the Pacific. In its new status as an imperial power, the United States followed a series of policies that were made to protect American territories and also to expand its international commercial interests.
The first twenty years of the XXth century saw the United States leadership pursue confidently intervensionist strategies in dealing with other countries. The three different diplomacies that were mentioned before by the first three presidents of the XX century, influence the American foreign policy because they started to intervene in other countries in order to gain power and to show them that they were powerful enough and also necessary to solve their problems. Also they wanted to show the world that they were really strong so other won't mess with them because if they do, they would lose.
The United States in the XX century demonstrate that they were a key player in the International System and  after the WWI the world saw the declive of the european power which was ruling the world for the last centuries, and saw the rise of a new power who was going to control the world for the next years.

References: 

• http://iws.collin.edu/kwilkison/Resources%20for%20Students/ForeignPolicy.html . Taken in March 14 of 2013 
• U.S DEPARTMENT OF STATE. http://history.state.gov/milestones/1899-1913/RooseveltandMonroeDoctrine. Taken in March 20 of 2013 
• U.S DEPARTMENT OF STATE.  http://history.state.gov/milestones/1899-1913/DollarDiplo . Taken in March 20 of 2013 
• Power point presentation by Luis Monroy