Asked by Casey

What ended the era of dual federalism?
Answered by Rachael
However, the departure from this view became evident with the ratification of the Sixteenth Amendment to the United States Constitution (income tax) as well as the Seventeenth Amendment to the United States Constitution (direct election of federal Senators).

-Wikipedia
Answered by Ms. Sue
This site may have the information you need.

http://en.wikipedia.org/wiki/Dual_federalism#Departure_from_this_view