Final answer:
The Roosevelt Corollary to the Monroe Doctrine was an approach articulated by President Theodore Roosevelt in 1904 that allowed the United States to intervene in the affairs of independent nations in the Western Hemisphere if they needed assistance.
Step-by-step explanation:
The Roosevelt Corollary to the Monroe Doctrine was an approach articulated by President Theodore Roosevelt in 1904 as an extension of the original Monroe Doctrine. The Roosevelt Corollary stated that the United States had the right and obligation to intervene in the affairs of independent nations in the Western Hemisphere if they needed assistance. This approach was used to justify American military interventions in countries such as the Dominican Republic, Nicaragua, Haiti, and others.