During the 1920' s, the Scopes trial and the dispute over Prohibition showed the clash between

The clash was between modern and the conservative values.

Explanation:

The 20s and the early 30s were really the watershed that defined American values for a long time to come.

Before then, the character of US was a decidedly fluid one.

It was a migrant's heaven, a land here anyone who can work hard enough will get the fruit for it.

But it had slowly grown a conservative population that did not like this openness and licentiousness of the Jazz age.

Ultimately they would triumph and identify themselves with the Right wing in the US and cause Prohibition.