which was the most severe example of the tension created by federalism?

civil war
passing the sedition act
nullification doctrine
refusing to pay tariffs

The most severe example of tension created by federalism was the Civil War. This conflict erupted due to deep-rooted disagreements between the Northern and Southern states over issues such as states' rights, slavery, and the balance of power between the federal government and state governments. The war resulted in massive casualties and immense damage to the nation.