premise: Well, there was an interest in having a uniform rule, and that's precisely why the Framers created the Copyright Clause in the Constitution, but there was copyright protection in some States, there wasn't copyright protection in other States, and what we know from the decision of this Court in the Wheaton decision is that there was not a common law copyright in existence. This Court explicitly held that. Now, the petitioners make this quid pro quo to draw the line as well as in how long a line
hypothesis: The framers created the copyright clause in the constitution because of the demand. 
reason: The Framers created the copyright clause in the constitution because there was interest (a demand) in having a uniform ruling. The system likely interpreted demand as meaning a forceful request rather than the the context of a need for something to be supplied (e.g. there was a demand for concert tickets)