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. 

the reform movements that arose during the antebellum period in america focused on specific issues: temperance, abolishing imprisonment for debt, pacifism, antislavery, abolishing capital punishment, amelioration of prison conditions (with prison's purpose reconceived as rehabilitation rather than punishment), the humane treatment of animals, the humane and just treatment of native americans, the establishment of public institutions for the care of the destitute, orphans, blind, and mentally ill, the establishment of public schools, the abolition of tobacco use, vegetarianism, health reform, homeopathic medicine, woman's rights (including, at first, especially the establishment of a woman's right to own property apart from her husband and her right to sue for divorce), and the amelioration of labor conditions (including higher pay, the right to form unions, the right to strike, and the demand for limits on the number of work hours, and safe working conditions).

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