- The Constitution itself which gives the power to the states to determine who are it's residents and how to record same (via birth records/certificates).
- By the State of Hawaii's laws that govern who are its residents and how same is registered within their state.
- U.S. Immigration and Nationalization law (as revised since 1952 which was the governing INA law that covers the President's birth).
- The Foreign Affairs Manual which supports INA law.
- Lower U.S. District courts have upheld the natural born status of children born to 1 U.S. citizen parent and 1 foriegner long before the issue came about over President Obama but subsequent to such Supreme Court cases, i.e., Minor v Happersett or U.S. v Wong Kim Ark.
- DNC By-laws which outline their vetting process for presidential candidates (which is actually stronger than the RNC By-laws).
When you put it all together, you really can't refute the evidence that's been presented nor the law. The man was born in Hawaii and meets minimum eligibility requirement under the U.S. Constitution to be this nation's 44th President. Those who disagree can bring about any law suit they wish; it is their right to do so. But I contend that without concrete evidence of the contrary, they'd be wasting their time.