American public opinion was turned in favor of independence by the popular pamphlet called?

It was called "Common Sense"

Yes it did because on this day in 1776, writer Thomas Paine publishes his pamphlet "Common Sense," setting forth his arguments in favor of American independence. Although little used today, pamphlets were an important medium for the spread of ideas in the 16th through 19th centuries.

Originally published anonymously, "Common Sense" advocated independence for the American colonies from Britain and is considered one of the most influential pamphlets in American history. Credited with uniting average citizens and political leaders behind the idea of independence, "Common Sense" played a remarkable role in transforming a colonial squabble into the American Revolution.