No, State Legislators Can't Ban Interstate Abortion Travel
The Constitution's commerce clause guarantees a domestic free trade zone. A state law that bars a resident from traveling to take advantage of another state’s economic activity would be unconstitutional.
The U.S. Supreme Court's recent decision in Dobbs v. Jackson Women's Health Organization, which eliminated the constitutional right to abortion, has prompted concerns that Republican-led state legislatures might try to prohibit women from traveling out of state for the procedure. Any such interstate travel ban would be constitutionally defective for at least two reasons.
First, the courts have repeatedly recognized that the Constitution protects the right to travel. During debates before ratification of the 14th Amendment, that right was specifically invoked as one of the privileges or immunities of citizenship that the amendment was designed to protect from state infringement.
Second, an anti-abortion interstate travel ban would run afoul of the Dormant Commerce Clause. That legal doctrine says the Commerce Clause in Article I of the Constitution not only allows congressional regulation of economic activity between the states but also forbids states from creating interstate economic barriers.
A primary purpose of the Commerce Clause, James Madison explained in Federalist No. 42, was to clear away the tariffs, monopolies, and other trade barriers that states had erected under the Articles of Confederation. "A very material object of this power," Madison wrote, "was the relief of the States which import and export through other states from the improper contributions levied on them."
Essentially, the Commerce Clause guarantees a domestic free trade zone. Under that principle, a state law that bars a resident from traveling to take advantage of another state's economic activity, such as the provision of abortion services, would be unconstitutional.
There is also case law dealing specifically with extraterritorial application of state abortion restrictions. In the 2007 case Planned Parenthood of Kansas v. Nixon, for example, the Missouri Supreme Court reviewed a state law that created a civil cause of action against any person who helped a minor obtain an abortion without parental consent either inside the state or in another state.
"Of course, it is beyond Missouri's authority to regulate conduct that occurs wholly outside of Missouri," the court observed. The law at issue, it said, "cannot constitutionally be read to apply to such wholly out-of-state conduct. Missouri simply does not have the authority to make lawful out-of-state conduct actionable here, for its laws do not have extraterritorial effect."