Antivivisectionists of the era believed the spread of mercy was the great cause of civilization, and vivisection was cruel. However, in the U.S., the antivivisectionists' efforts were defeated in every legislature because of the widespread support of an informed public for the careful and judicious use of animals. The early antivivisectionist movement in the U.S. dwindled greatly in the 1920s, potentially caused by a variety of factors including the opposition of the medical community, enormous improvements in medicine through the use of animals, and the tendency of the antivivisectionists to misrepresentation and exaggeration, and their use of inaccurate, vague and outdated references.