Many people believe a President can only pardon federal crimes. This belief is common, but it does not clearly come from the Constitution, nor is it explicitly codified in the text of the pardon clause. Instead, it arises from tradition and later court practice.
When the Constitution is read closely, a different and reasonable argument appears.
The Constitution places judicial power in the federal government. Article III, Section 1 states: “The judicial Power of the United States, shall be vested in one supreme Court…” It creates only one Supreme Court. Other courts exist only if Congress chooses to create them: “…and in such inferior Courts as the Congress may from time to time ordain and establish.”
Article III, Section 2 opens with an important sentence: “The judicial Power shall extend to all Cases, in Law and Equity, arising under this Constitution…” The words “shall” and “all Cases” are not narrow. The Founders do not limit judicial power to cases labeled “federal” by statute, which is a congressional distinction among lower courts allowed to exist under the Supreme Court. Instead, they extend judicial power to all cases arising under the Constitution. This places ultimate judicial authority in the United States, not in separate and equal state systems.
The Constitution also establishes federal supremacy. Article VI, known as the Supremacy Clause, states: “This Constitution, and the Laws of the United States which shall be made in Pursuance thereof… shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby.” State judges are explicitly required to follow federal law. A court that is bound by a higher authority is not a separate sovereign in the full sense of the word. It operates within a hierarchy.
That hierarchy arises from Congress’s authority to approve ratification of the federal Constitution and to admit states into the Union. Ratification by a state includes acceptance that there is one Supreme Court, that judges within the state are subordinate to the Constitution and that Court, and that state court decisions are subject to review by a higher federal authority.
The Supreme Court recognized this structure early. In Martin v. Hunter’s Lessee (1816), the Court explained that the Constitution created one Supreme Court and allowed federal review of state court decisions involving federal law. In Cohens v. Virginia (1821), the Court held that even state criminal cases fall within federal judicial power when constitutional issues are present. In McCulloch v. Maryland (1819), the Court stated plainly that the Constitution and federal laws “are supreme” and control state law.
Some argue that the Tenth Amendment preserves independent state judicial sovereignty. But the Tenth Amendment only reserves powers that were not delegated. It states that powers “not delegated to the United States” are reserved to the states. Judicial power is expressly delegated in Article III. Because it was delegated, the Tenth Amendment does not reclaim it. Reserved powers cannot include powers already assigned.
Yes, state courts existed before the Constitution under the Articles of Confederation. That system failed and was replaced. When the Constitution was adopted, the Articles were dissolved and a new legal order was created. State courts continued to operate, but under federal supremacy, not independent judicial sovereignty, and they agreed to this upon ratification. New states were admitted by Congress under the same constitutional framework. Maintaining courts is not the same as retaining supreme judicial power.
Therefore, the idea of “dual sovereignty,” in which state and federal governments operate as fully separate criminal authorities, does not appear in the Constitution. The phrase is not used. No provision creates two supreme judicial systems. No provision recognizes retained sovereign judicial power in the states. The concept developed later through judicial interpretation and practice, not constitutional text. The Constitution states the opposite: that its laws and judicial power are Supreme.
Further, the President’s pardon power is written broadly. Article II, Section 2 states that the President “shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment.” Only one exception is stated. State offenses are not mentioned. Limiting the pardon power to federal-only crimes requires reading an additional exception into the text that does not appear there.
While supporters of the modern system often rely on tradition, tradition does not amend the Constitution. The Supreme Court has said this directly. In Reid v. Covert (1957), the Court stated that “the Constitution cannot be amended by practice.” In INS v. Chadha (1983), the Court invalidated a long-used government practice, reaffirming that habit does not override constitutional structure.
This does not mean courts will accept a presidential pardon of a state conviction today. It means the argument for such a pardon rests on constitutional text and structure rather than political preference. If judicial power belongs to the United States, if state courts are bound by federal supremacy, if judicial power was expressly delegated, and if the pardon clause contains no state exception, then a presidential pardon of a state conviction is constitutionally arguable.
The Constitution creates one supreme law and one Supreme Court. It grants the President broad pardon power with one explicit limit.
Tradition may explain how the system has operated, but it does not change what the Constitution says.