More on Hoover as Proto-New Dealer:
Herbert Hoover--the "Forgotten Progressive"--also nominated three Justices to the Supreme Court: Charles Evans Hughes (February 24, 1930--June 30, 1941) replacing Chief Justice Taft, Owen Roberts (June 2, 1930--July 31, 1945) replacing Justice Sanford, and Benjamin Cardozo (March 14, 1932--July 9, 1938). In O'Gorman and Young v. Hartford Fire Insurance Co, 282 U.S. 251 (1930), the Supreme Court began the so-called "New Deal Revolution" a few years early. In O'Gorman, it adopted what it called a "presumption of constitutionality" in place of the Progressive Era Supreme Court's requirement that a legislative interference with liberty be justified as reasonable. Here is a summary of the case from the The Oxford Companion to the Supreme Court of the United States:
O'Gorman is a turning point case in the field of economic due process. One of the last liberty of contract cases, it involved a New Jersey statute regulating the fees paid to local agents by insurance companies. The statute was challenged as a violation of the Fourteenth Amendment's Due Process Clause. Contending that the facts surrounding its origins and operation should be determinative, Justice Louis Brandeis sustained the statute. He found that the presumption of constitutionality must prevail in the absence of some factual foundation of record for overthrowing the statute" (p. 258). Further, legislative judgment must prevail unless it could be demonstrated that the measure was utterly arbitrary. No such demonstration had been made. The business of insurance, he argued further, is so far affected with a public interest that the state may regulate the rates as a subject clearly within the scope of the police power. He further contended that the Court should cease using the Due Process Clause in a "substantive" manner to second guess the legislature.

The four dissenters [Van Devanter, McReynolds, Sutherland, and Butler] vigorously propounded freedom of contract, restrictive alteration of the public interest doctrine, and the pressing obligation to check any legislative interference with property. They particularly objected to the idea that the right to regulate business implied the power to trespass on the duties of private management. The majority opinion, however, made clear that the constitutionality of state regulation of the economy should no longer turn on the question of its unreasonableness.
The vote was 5-4 with Chief Justice Hughes and Justice Roberts tipping the balance. Indeed, the case was originally argued on April 30, 1930, after Hughes replace Taft but more than a week before Hoover nominated Roberts. With the Court presumably divided 4-4, O'Gorman was held over for reargument until October 30th, after which Roberts was able to form a new majority adopting the presumption of constitutionality. (See Barry Cushman's, Rethinking the New Deal Court, p. 76.) Less than two years later, Hoover nominee Cardozo replaced Justice Brandeis who wrote the opinion in O'Gorman. In this way, it was Hoover's nominees who began seriously undermining the Due Process scrutiny of the Progressive Era Court--the approach identified with Lochner v. New York--well before Roosevelt had a chance to appoint anyone to the Supreme Court.