What was America’s foreign policy before we became involved in WWI? What two events occurred that changed America’s thinking and led to approval of the U.S. entering the war?

Isolationism

Explanation:

America’s foreign policy before we became involved in WWI was isolationism. We became involved when Germany sunk the Lusitania, which is a British passenger ship. Another reason for involvement was the Zimmerman Telegram. Which was a letter from Germany to Mexico stating that Mexico should attack the US if the US goes to war with Germany (needed that advantage due to Mexico's proximity to the US). In return, Germany would give back Texas, New Mexico, Arizona, etc to Mexico.