The public debate about proper judicial reasoning is often so ill-informed because the focus is only on short-term partisan agendas, a bad habit which damages the fabric of our society and respect for the rule of law.
Into that morass and using the recent Supreme Court decision on medical marijuana use in California, Charles Krauthammer elaborates on the meaning of “original intent” and shows how far away the courts have moved away from a strict interpretation of the Constitution. Here is the link to his very helpful and educational editorial on judicial reasoning:

…In our current, corrupted debates about the judges, you hear only about results. Priscilla Owen, we were told (by the [ultra-liberal] Alliance for Justice), “routinely backs corporations against worker and consumer protections.” Well, in what circumstances? In adjudicating what claims? Under what constitutional doctrine?
The real question is never what judges decide but how they decide it. The Scalia-Thomas argument…was about what the Constitution’s commerce clause permits and, even more abstractly, who decides what the commerce clause permits. To simplify only slightly, Antonin Scalia says: Supreme Court precedent. Clarence Thomas says: the Founders, as best we can interpret their original intent.
The Scalia opinion (concurring with the majority opinion) appeals to dozens of precedents over the past 70 years under which the commerce clause was vastly expanded to allow the federal government to regulate what had, by the time of the New Deal, become a highly industrialized country with a highly nationalized economy.
Thomas’s dissent refuses to bow to such 20th-century innovations. While Scalia’s opinion is studded with precedents, Thomas pulls out founding-era dictionaries (plus Madison’s notes from the Constitutional Convention, the Federalist Papers and the ratification debates) to understand what the word commerce meant then. And it meant only “trade or exchange” (as distinct from manufacture) and not, as we use the term today, economic activity in general. By this understanding, the federal government had no business whatsoever regulating privately and medicinally grown marijuana.
This is constitutional “originalism” in pure form. Its attractiveness is that it imposes discipline on the courts. It gives them a clear and empirically verifiable understanding of constitutional text — a finite boundary beyond which even judges with airs must not go.
And if conditions change and parts of the originalist Constitution become obsolete, amend it. Democratically. We have added 17 amendments since the Bill of Rights. Amending is not a job for judges.
The position represented by Scalia’s argument in this case is less “conservative.” It recognizes that decades of precedent (which might have, at first, taken constitutional liberties) become so ingrained in the life of the country, and so accepted as part of the understanding of the modern Constitution, that it is simply too revolutionary, too legally and societally disruptive, to return to an original understanding long abandoned.
And there is yet another view. With Thomas’s originalism at one end of the spectrum and Scalia’s originalism tempered by precedent — rolling originalism, as it were — in the middle, there is a third notion, championed most explicitly by Justice Stephen Breyer, that the Constitution is a living document and that the role of the court is to interpret and reinterpret it continually in the light of new ideas and new norms.
This is what our debate about judges should be about. Instead, it constantly degenerates into arguments about results.
Two years ago, Thomas (and Scalia and William Rehnquist) dissented from the court’s decision to invalidate a Texas law that criminalized sodomy. Thomas explicitly wrote, “If I were a member of the Texas Legislature, I would vote to repeal it.” However, since he is a judge and not a legislator, he could find no principled way to use a Constitution that is silent on this issue to strike down the law…

As we approach a time of new Supreme Court nominations, it would be a service to the country if the Senate and the major interest groups across the political spectrum could conduct a reasoned public debate on these important principles.
Since we know that they have lost the ability to conduct that kind of debate over the last 20 years, recovering such a debate will only occur if the requisite public pressure from citizens across America demands it. I hope we are up to the challenge.

ADDITIONAL INFORMATION:
Here are other postings on this site about the related issue of the judicial filibuster debate:
The Filibuster…Continued
The Injustice of Smearing A Fellow American For Political Gain
The Senate Judicial Filibuster: Power Politics & Religious Bigotry
Mac Owen’s open letter to Senator Chaffee
Senator Mitch McConnell on the Judicial Filibuster
The Foolish Fourteen: An editorial by the former Dean of BU’s Law School
A Power Line overview of the filibuster debate
Revisiting the Case for Janice Rogers Brown