Question

Why did the rosenburg case attract nationwide attention and controversy

Answer 1

Gradpiont!

The case against Julius and Ethel Rosenberg was based largely on the word of one confessed spy.

Answer 2

Julius and Ethel Rosenberg were American citizens who spied on the United States on behalf of the USSR, giving confidential information about jets, radar, and more.

This attracted much attention as the United States was in the midst of a "red scare" where everyone was afraid of communist infiltration. The Rosenbergs gave tangible proof that the USSR was in fact infiltrating the USA.