Final answer:
The 1823 U.S. policy referred to in the question is the Monroe Doctrine, which intended to protect the western region from European colonization and strengthen U.S. territorial integrity.
Step-by-step explanation:
The 1823 U.S. policy hoped to protect the western region. The Monroe Doctrine, articulated in President James Monroe’s annual message to Congress, was aimed at protecting the Western Hemisphere from European colonization and interference. This doctrine emphasized that the Americas were no longer subject to European colonization, and it marked a significant moment in U.S. foreign policy, promoting a spirit of isolationism with respect to European colonial affairs. It laid the groundwork for U.S. expansion across the North American continent, securing a path to the Pacific Ocean and supporting the territorial integrity of the United States.