How does the supremacy clause impact disputes among states or between states and the national govt?

Supremacy clause precisely means that the Constitution of the United States is the Supreme law of the Land. Although in general the states or federal government will have power over the citizens or in their respective jurisdictions. In case of any dispute between states or states and federal government, supremacy clause tells that federal laws will supersede the state law or local authority. 

what the first or next guy says

a woodchuck would chuck 12.5 wood : 3