During World War I, the Ku Klux Klan skyrocketed in popularity across America. How did the war encourage Americans to join a group that practiced discrimination?

The reason is that there were more black people left behind so the animosity began to climb.

Explanation:

The time of the war was one in which many young Americans were dying and it was also when the south had been radicalized against the blacks and had begun to blame them.

This was also because of the low number of drafts  from that part of the country.

So, the Klan took advantage of the public opinion and drastically increased its numbers and in the frenzy of the war people began to join.

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