Basically Law

Read the opinion here.

Issue.  Can a treaty's obligations bind a State even though the Federal Government lacked Article I power to pass such an obligation absent a foreign treaty?

Background.  In 1916, the United States and Great Britain signed the Migratory Bird Treaty.  The treaty was subsequently approved by two-thirds of the Senate.  Under the terms of the treaty, the United States agreed to limit the hunting of certain birds that flew over the United States.  In order to enforce that provision, among others, Congress passed the Migratory Bird Treaty Act.

The State of Missouri brought an action against the United States game warden to prevent enforcement of the law.  Missouri claimed that Congress lacked the power under Article I to pass such a law.  The case was appealed to the Supreme Court which found that the law was constitutional.

Court's Analysis.  The Court found that if a treaty is valid, then any legislation passed to enforce the treaty is constitutional under the Necessary and Proper clause.  Contrary to the argument of Missouri, a treaty can be valid even if it infringes the constitution.  The only question for the Court was whether the treaty was forbidden by some "invisible radiation from the general terms of the Tenth Amendment."

The Court did not find such a "radiation."  In fact, there was no Tenth Amendment violation at all (even if there was not a treaty).  There was a national interest of the first magnitude involved.  It could only be resolved through a national solution - a treaty in this case.  The States could not be trusted to prevent the destruction of a food supply or habitat.  Thus, the treaty and statute must be upheld.

Afterword.  Even though the Court claimed that some treaties could violate the Constitution, it is difficult to conceive of such a situation.  Can Congress get around Article I by signing treaties and then laws to enforce them?  Or, is this a situation, where, based on the facts, we can discern whether the Federal Government is signing a valid international treaty or is trying to circumvent the Tenth Amendment.

The latter seems plausible.  This is one of the possible "loopholes" in the Constitution, but it has not come to fruition because of the institutional respect for the spirit of the Constitution.  Congress, however, was so concerned about the exploitation of this loophole that is was prepared to amend the Constitution.

The attempt failed and Congress's fears were allayed in Reid v. Covert, where the Supreme Court noted that treated had to conform to the Constitution and that the Court in Missouri v. Holland did not find a Tenth Amendment violation.