In the case of First National Bank of Gulfport, Mississippi v. Adams, Revenue Agent of the State of Mississippi in 1921, the bank challenged a state law that taxed national banks at higher rates than other moneyed capital in the hands of individual citizens or corporations. The Supreme Court ruled against First National Bank and upheld Mississippi's tax law as constitutional. The court found that while federal laws do prohibit discriminatory taxation on national banks by states, they do not guarantee absolute equality with all forms of taxes imposed on local businesses or individuals. Therefore, it was permissible for states to impose different types and levels of taxes on different entities as long as there is no clear discrimination against national banks specifically because they are nationally chartered institutions.

The dissenting opinion in the case of First National Bank of Gulfport, Mississippi v. Adams argued that the majority's decision to uphold a state tax on national banks was inconsistent with federal law and precedent. The dissent contended that Congress had intended to exempt national banks from such taxes when it passed legislation regulating these institutions, as part of an effort to encourage their growth and stability. It also pointed out previous Supreme Court decisions which held that states could not impose taxes on federal entities without explicit congressional authorization. Therefore, according to the dissenting justices, Mississippi's tax was invalid because it conflicted with both statutory law and judicial precedent protecting national banks from state taxation.