Final answer:
The sinking of the Lusitania was important to President Wilson's foreign policy because it led to the United States declaring war on Germany in 1917.
Step-by-step explanation:
The sinking of the Lusitania was important to President Wilson's foreign policy because it ultimately led to the United States declaring war on Germany. The sinking of the Lusitania, a British passenger ship, by a German U-boat in 1915 resulted in the death of over 1,200 civilians, including 128 Americans. This event created a shift in American sentiment and increased pressure on President Wilson to take action. As a result, Wilson asked Congress to declare war on Germany in April 1917.