Final answer:
William Lloyd Garrison was the founding editor of The Liberator, an influential abolitionist newspaper that was published for 35 years until the end of slavery in the U.S.
Step-by-step explanation:
The founding editor of The Liberator, the major abolitionist newspaper, was William Lloyd Garrison. Garrison was known for his militant advocacy for immediate and complete emancipation, seeing it as a moral imperative. He insisted on racial equality and the elimination of laws that restricted the political and civil liberties of free African Americans, maintaining his position even in the face of opposition. The Liberator played a critical role in the abolitionist movement, being published continuously for 35 years until the end of slavery in the United States.