One good reason to proove that Theodore Roosvelt was a heavy-handed imperialist is that He had been hurting long-term relations with Latin America as they resented US involvement, due to national interests. He used an massive interventionism, regardless of the relations of other countries, in order to prove the place of America, its role, in the world.
Roosevelt Corollary, amendment to the Monroe Doctrine, considered as a self-appointed police.