The McCulloch v. Maryland case involves a state's attempt to tax a federally created bank $15,000/year; it was a landmark decision because of its ruling that subordinated the power of the state to that of the federal government. The ruling of the Supreme Court stated, 

Because federal laws have supremacy over state laws, Maryland had no power to interfere with the bank's operation by taxing it.

This ruling is one of the most important rulings on the expansion of Federal power; for, it overturned the ruling of the Maryland courts that the state could tax the bank, holding that Congress has implied powers that are derived from those in Article I, Section 8 in which the "Necessary and Proper" clause affords Congress the power to establish a national bank.

Included in his ruling is Chief Justice Thurgood Marshall's statement that if the state of Maryland could have the power to tax the federally established bank, then states could tax other federal institutions, and, thus make the states more powerful than the federal government.

That the power to tax involves the power to destroy....If the states may tax one instrument employed by the [federal] government in the execution of its powers, they may tax any and every other instrument...

Marshall's decision also confirms the subordination of the Articles of Confederation to the U.S. Constitution. For, Marshall argued that while the Articles affirm that the states retain all powers not "expressly" given to the federal government, the Tenth Amendment to the Constitution does not include the word expressly; therefore, the Congress is not limited to the powers which are specifically listed in Article 1.