I'm posting these cartoons in the forum's Progressive Media section b/c of the political leaning of its creator and that of the publication from which it's taken.
Background:
America in the 1920s and '30s was marked by hardening attitudes toward aid to the victims of war and the immigration of refugees fleeing totalitarian domination in Europe. In 1940, a year before the attack on Pearl Harbor, one organization formed which shared this attitude: the anti-interventionist America First Committee -- which Geisel referenced here --

America-Firsters promoted isolationism and using American resources to build a wall of strength which foreign enemies could never penetrate --

Aviator Charles Lindbergh was America First's most rabid, and most popular, spokesperson.

For more info, see: http://www.snopes.com/dr-seuss-adolf-wolf/
-Marie-