President Monroe's foreign policy, called the Monroe Doctrine, was remarkably similar to that of a later president, Theodore Roosevelt. Roosevelt famously said that, when it came to foreign policy, one should "speak softly, but carry a big stick". What he meant by this was that, while one should always strive to maintain good relations with foreign countries, it was important to use force when necessary to defend national interests. This, in a nutshell, was the same attitude embodied in the Monroe Doctrine.
Monroe believed his doctrine was the best way of maintaining peace between the United States and Europe, especially Great Britain. By dividing up the world into precise spheres of influence, Monroe hoped to avoid the kind of territorial disputes which had plagued international relations for generations.
At the same time, Monroe's desire for peace was balanced by a readiness to use force should any nation trespass upon the United States' sphere of influence in the western hemisphere. In effect, Monroe was saying to the old colonial powers of Europe that, while he wanted to have peaceful relations with them, the United States would stoutly defend its interests in the western hemisphere, by force if necessary.