Which process allows for informal changes to the Constitution?

Judicial interpretation is the correct answer because it refers to the way in which courts, particularly the Supreme Court, interpret the Constitution in their rulings. Through judicial review, judges are able to provide meanings and applications of constitutional provisions that can evolve over time, adapting the Constitution to contemporary circumstances and societal values without the need for a formal amendment. This process can significantly change the understanding and implementation of constitutional principles, reflecting the dynamic nature of law in response to new situations, legal precedents, and societal needs.

The other choices do not encapsulate the idea of informal changes effectively. The amendment process involves formal modifications to the Constitution, requiring significant consensus and deliberation by the legislative bodies. The presidential veto refers to the authority of the president to reject legislation, which does not directly change the Constitution. State legislation, while influential, primarily operates within the framework of existing laws and the Constitution; it does not directly enact changes to the Constitution itself.