What you put in quotes is NOT my claim at all, and my logic is not circular in the least.DMF, your reasoning seems circular to me. "There is a federal law, therefore it is a federal issue. Because it is a federal issue, we can pass more federal laws making more things federal issues."
My logic is as follows:
Congress is given specific authority in the Constitution to address specific federal interests (aka issues) via legislation. There must first be a federal interest for Congress to properly address that interest with legislation. If they legislate in areas where there is no established federal interest then the law is able to be successfully challenged in the courts.
If they address a federal through legislation, the executive has a chance to veto or sign it into law. Further the laws may also be challenged in the courts. Finally, if there are laws there must be a mechanism to enforce those laws, which is why federal law enforcement agencies were created along with the very first laws, at the very first Congress.