Justice Black was a Roosevelt appointee and a Klan member -- I'm not sure I trust his opinions on anything.
I mentioned in the original post that he was an FDR appointee and a KKK member. He was also a New Deal Liberal and fought for the court-packing scheme while in the Senate. Yet, ironically, he is perhaps the one Justice of the 20th Century who was the most wedded to the actual text of the Constitution.
It's not a question of trust. Do you agree with his dissent in Griswold?
In fairness to Hugo Black, he was a pretty good judge. I think he did stretch certain constitutional passages beyond their breaking point (the Commerce Clause) to uphold some popular federal legislation. I guess that's why FDR put him on the court. But he did respect popular sovereignty to a good degree and didn't hate the Constitution. He didn't feel himself to be a philosopher king entitled to mow down any law he didn't like under the guise of "updating the Constitution to fit modern times". If he were on the court today he'd be to the right of most of the sitting justices and not much to the left of Scalia & Thomas.
As for his KKK membership, it occurred in the twenties, at the height of KKK power. The Klan then controlled the Democratic Party in several states. If you wanted to run for office in a Democratic precinct, you sort of had to pay your KKK membership dues. Harry Truman did it in Missouri, though he reportedly claimed that the $10 annual dues were too high. As ridiculous as it seems today, joining the KKK before filing to run for office was similar to joining the Kiwanis club in some parts of the country. Black's KKK involvement was largely token membership necesary to get his foot inside the political door.