Lamar, Executor v. McCulloch is a United States Supreme Court case that was decided in 1879. The case involved a dispute between the executor of a deceased man's estate and a bank. The executor, Lamar, had sued the bank, McCulloch, for failing to pay a debt owed to the estate. The Supreme Court ultimately ruled in favor of the bank, McCulloch. The Court's decision was based on the interpretation of the Constitution. The Court held that the Constitution did not give the states the power to tax the federal government or its agencies. The Court reasoned that the federal government had the power to create a bank, and the states did not have the power to interfere with the bank's operations. The Court also held that the states could not interfere with the bank's ability to collect debts. The Court's decision was significant because it established the principle of federal supremacy. The Court held that the federal government had the power to create and regulate its own agencies, and the states could not interfere with those agencies. This decision has been cited in numerous cases since then, and it has been used to support the idea that the federal government has the power to regulate its own agencies and that the states cannot interfere with those agencies.

In Lamar, Executor v. McCulloch, the Supreme Court was asked to determine whether a state law could be used to tax federal bonds held by a national bank in that state. The majority opinion found that such taxation was unconstitutional because it interfered with Congress’s power over the nation's money and banking system as granted by Article I of the Constitution. However, Justice Field dissented from this decision on two grounds: firstly, he argued that states have an inherent right to tax property within their borders; secondly, he argued that since Congress had not specifically prohibited such taxation in its legislation creating national banks or regulating them through charters issued under its authority then it must be assumed they intended for states to retain their taxing powers over these entities. Ultimately Justice Field believed there was no constitutional impediment preventing states from imposing taxes on federal bonds held by national banks located within those respective states' boundaries.