If you assume the 1961 document is valid and not a fabrication.
The fabrication argument has had difficulty gaining traction with Congress and in the courts over the last six years because the state of Hawaii has issued eight statements of verification and authentication for the original birth certificate, beginning in 2008 and across both Republican and Democratic administrations.
The “Full Faith and Credit” clause of the Constitution (Article IV, Section 1) and the Federal Rules of Evidence on Self-authenticating documents (Rule 1005) say that whatever public record a state says is valid and authentic must be accepted in every other jurisdiction. None of the many challenges to the authenticity of the original birth record has been able to overcome Hawaii’s statements, yet.