Missouri Gov. Jay Nixon has vetoed a bill on foreign laws, saying the measure would create barriers to adoptions from other countries.

The bill would have made court rulings unenforceable if they were based on any foreign law or system considered “repugnant” or inconsistent with the constitution.

Adoption advocates raised concerns about how that could affect adoptions completed in another country.

Nixon announced the veto Monday. The governor says the bill would have created uncertainty in Missouri’s legal system and could have had a “chilling effect on foreign adoptions.”

Supporters said the legislation was designed to prevent Missouri courts from using policies that come from outside the U.S. and violate constitutional protections.