Your analysis of the Commerce clause is correct. Not only is it a pre-emptive provision guaranteeing federal regulation, but it is also protective of those who engage in interstate commerce.

It is also floating police power which serves as the basis to enable Congress to enact legislation to enforce it. As a young kid during the late 60's I was involved in the civil rights movement. The Commerce Clause serves as the underpinning for the Civil Rights Act of l964.

There are also the penumbral rights of the Constitution, which not expressly stated in the Constitution have been held to exist by the U S Supreme Court. For example...a woman's right to choice is based on the penumbral guarantees of the U S Constitution.

Issues involving the Commerce Clause would satisfy the federal question by which litigants can claim the federal court's jurisdiction.