Answer:
New York vs the U.S. case.
(Check the last paragraph for the second part).
Step-by-step explanation:
There have been many cases between the state government and the federal government in which the federal government wants to dominate the stats government. One of the cases that had the most significant effect on the balance of power between federal and state governments is that of the New York vs the U.S. case.
In the New York vs the U.S. case, the federal government wants to force the state government to adopt the federal government policies and regulations concerning how radioactive waste are being disposed.
The case has more significant than the others I have researched because the United States of America practices Federalism and power most be balanced between the state and the federal government. The federal government has no power over the state government so it had no right to force the state government in adopting the regulation.