I’m not familiar with the particular history you speak of...about how SCOTUS ruled on Feds and insurance, while congress passed a law to give it back to the states. Please inform me what case or link I could look at.
United States v. South-Eastern Underwriters Association, 322 U.S. 533 (1944)
http://en.wikipedia.org/wiki/United_States_v._South-Eastern_Underwriters_Association
Another of the New Deal rulings that expanded federal powers.
Paul v. Virginia, 75 U.S. (8 Wall) 168 (1869), was a historic case in corporate law in which the United States Supreme Court held that a corporation is not a citizen within the meaning of the Privileges and Immunities Clause. Of greater consequence, the Court further held that “issuing a policy of insurance is not a transaction of commerce,” effectively removing the business of insurance beyond the United States Congress’s legislative reach.
That was the precedent in 1944...overturned by the New Deal court.