What was Zinn's argument about World War I in A People's History of the United States?

In Chapter
Fourteen, Zinn argues that the official justification for American involvement in the warthat it
was undertaken to protect free trade and other rights of nationsis nonsense. He quotes historian
Richard Hofstadter, hardly a radical, who dismissed this as "rationalization of the
flimsiest sort." Zinn finds the real motives for entering the war in what Wilson called the
"righteous conquest of foreign markets" and a desire to achieve profits for
industrialists and financiers while promoting unity with the working classes. American
involvement in the war would open up tremendous opportunities for war profiteers, and victory
would ensure expanded American access to global markets. Zinn notes that J.P. Morgan and Company
issued massive loans to Great Britain, which obviously gave them a motive for seeing Allied
victory, even (or more accurately, especially) if that meant American intervention. Zinn spends
most of this chapter writing about how the American state sought to maintain a consensus for
fighting the war through propaganda, suppression of dissent, and especially crushing
working-class unrest. Socialist opposition was especially strong, as evidenced by Eugene V. Debs
and Charles Schenck, both imprisoned for voicing their distaste for the war, and the actions of
the International Workers of the World. In short, to enforce consensus on a war that many
Americans did not want, the "establishment" in the United States resorted to decidedly
undemocratic measures:

The patriotic fervor of war had
been invoked. The courts and jails had been used to reinforce the idea that certain ideas,
certain kinds of resistance, could not be tolerated.