The Preamble to the Constitution has an important but limited function in constitutional interpretation.
Here are two related thoughts about the Fugitive Slave Clause.
State Action: It is often said that the Constitution only imposes obligations on government officials. While that may be generally true, it is not clear that it is entirely true. One famous example is the 13th Amendment, which simply prohibits slavery, rather than prohibiting the federal government or the states from imposing slavery. (“Neither slavery nor involuntary servitude . . . shall exist within the United States, or any place subject to their jurisdiction.”)
It is often argued that the 13th thus prohibits private persons from participating in slave relations. While this is certainly a plausible interpretation of the Amendment, I genuinely don’t know if it is correct.
The other day, however, I came upon a couple of other clauses that may not have government action requirements. The Fugitive Slave Clause provides that “No person held to service or labor in one state, under the laws thereof, escaping into another, shall, in consequence of any law or regulation therein, be discharged from such service or labor, but shall be delivered up on claim of the party to whom such service or labor may be due.”
Does this Clause require private citizens to deliver up fugitive slaves on claim of the alleged owner? The language does not explicitly restrict itself to government officials. But one might think it was implicit, especially as the first part of the sentence seems addressed to the state, as it asserts that no law or regulation should operate to free the fugitive slave. Again, I genuinely don’t know what is the correct reading.
A similar question arises as to the Extradition Clause, which provides: “A person charged in any state with treason, felony, or other crime, who shall flee from justice, and be found in another state, shall on demand of the executive authority of the state from which he fled, be delivered up, to be removed to the state having jurisdiction of the crime.”
Enforcing the Fugitive Slave Clause: The Fugitive Slave Clause is sadly one that was in my view misinterpreted from the beginning. The Clause does not provide Congress with a power – it is purely about prohibiting certain state laws (freeing fugitive slaves) and placing an obligation (to return fugitive slaves). Thus, the Necessary and Proper Clause could not be used by Congress to pass laws enforcing the Clause. Consequently, the Fugitive Slave Act of 1793 was unconstitutional, even though the Supreme Court approved it in Prigg v. Pennsylvania.
If the Fugitive Slave Clause could not be enforced by Congress, how could it be enforced? Mainly through the courts. If a state purported to free a fugitive slave, that law would be unconstitutional. What if a state official (or an individual, assuming no state action requirement) refused to return a fugitive slave? Presumably, an injunction could be obtained against the official (but perhaps not the state), requiring him to do so.