The state of Maryland believed that it could ignore federal banking policy established with the creation of the Second Bank of the United States because the power to create a national bank was not explicitly given to the federal government in the constitution.
This idea of the federal government having the ability to do something even though it is not written in the constitution is called an implied power. However, during this time (early 1800's), individuals were still disagreeing over what powers the federal government could imply. This crisis over the constitution and its interpretation will be seen several times throughout the early 1800's.