The Roosevelt Corollary's goal was to

to prevent European forces on the soil of Americas.

Explanation:

Since the 19th Century and Monroe's doctrine, United States tried to prevent European countries to interfere in the internal conflicts and problems on the American continent. Roosevelt believed that United States are the ones that have the obligation to prevent conflicts and to create a peaceful environment especially in the region of the Caribbean. United States in that sense behaved like a police that will prevent problems.