What is the Most probable problem of a federal system?

One of the most probable problems of a federal system is the potential for conflict between state and federal governments, leading to issues of jurisdiction and authority. This can result in inefficiencies, inconsistencies in laws and policies, and challenges in governance, particularly when states enact laws that contradict federal legislation. Additionally, disparities in resources and capacities among states can exacerbate inequalities, making it difficult to implement uniform policies effectively across the federation.