If the Court is going to decide constitutionality, the ONLY reference to be cited is the US Constitution - not previous Court decisions, Congressional intent, common sense, or any other source. The US Supreme Court has authority to apply the law to the situation, nothing more.

Far too often, the Supreme Court justifies it's decisions or dissents on opinion and rhetoric. The US Constitution does not include a provision for "original intent", it simply says these are the rules, make Amendments when necessary. There is also no constitutional provision for judicial interpretation. And it is not only a set of guidelines. Article 6 of the Constitution states "this Constitution... is the supreme law of the land". If there is a lack of clarity, or if the issue is not addressed by law, the proper remedy is an Amendment for constitutional issues, or legislation - by either Congress under their constitutional powers, or the state legislatures according to theirs.

Here are several quotes that make the point very well:

"The Constitution is a written instrument. As such, its meaning does not alter. That which it meant when it was adopted, it means now" South Carolina v. United States, 199 U.S. 437, 448 (1905)

"There are 'absolutes' in our Bill of Rights, and they were put there on purpose by men who knew what words meant and meant their prohibitions to be 'absolutes.'" - Supreme Court Justice Hugo Black

"The Constitution was written to be understood by the voters; its words and phrases were used in their normal and ordinary, as distinguished from technical meaning; where the intention is clear, there is no room for construction, and no excuse for interpolation or addition” - Cooley’s Constitutional Limitations, Second ed., p. 61, 70.

"It will be of little avail to the people that the laws are made by men of their own choice if the laws be so voluminous that they cannot be read, or so incoherent that they cannot be understood”. - James Madison