President Fred Vinson
Fred Vinson is one of the more obscure Chief Justices and is widely seen as a mediocre member of the Court. He was appointed by President Truman in 1946 (the last Chief Justice from the Democratic Party) and served until he died in 1953. As Carlton Larson pointed out in this terrific piece a few years ago, Vinson would be viewed very differently if he had written Brown, which he almost surely would have he had not died when he did. Vinson penned the opinions in Shelley v. Kramer, Swett v. Painter, and McLaurin v. Oklahoma striking down racial segregation, and there is no reason to think that he could not have in Brown (though whether it would have been unanimous is another question).
What I didn’t know until recently is that Truman really wanted Vinson (a former Congressman and Treasury Secretary) to succeed him as President. He tried to talk Vinson into running in 1952, and with Truman’s backing Vinson would have been a formidable candidate for the Democratic nomination. Vinson declined, though, partly for health reasons and partly because he felt that a Chief Justice should not reenter politics.