Simplify the following text for a Grade 7 native English-speaking person.
Original: The Carter Doctrine was a policy proclaimed by President of the United States Jimmy Carter in his State of the Union Address on January 23 , 1980 , which stated that the United States would use military force if necessary to defend its national interests in the Persian Gulf region .
Simplified: The Carter Doctrine by President Jimmy Carter stated that the U.S. would use military force to protect its interests in the Persian Gulf .