Originalist Progressives?

Over at The New Republic, a couple of Yale law profs post an article on how Progressives can use the principles of Originalism to achieve their ends. They have this to say to sum up their argument:

Quite simply, then, progressives can argue that they are committed to achieving the Constitution's purposes. Protecting equal citizenship in work, education, and the family is necessary to establish the democracy the Constitution seeks to secure. Subordinating arbitrary executive power to the rule of law is necessary to safeguard the freedom the Constitution exists to preserve. Enabling the federal government to meet the needs of its citizens is necessary to sustain the powerful nation the Constitution seeks to create.

If I was a little unclear on exactly how their approach was not just the same old Progressivist creedo that I've always heard, this paragraph confirms that it is simply that. Spinning the Constitution to mean whatever we'd like to think it should mean, or it should have said, is the same Progressivist plot as ever. And it necessarily raises the question, why would anyone create a constitution in the first place? We can look to the common law and ratification debates and the Federalist Papers just as well without the Constitution. The Progressivist view belittles the Constitution to something on the order of a formal memo rather than a framing document.