I do think that you can be a brilliant scientist as well as being a person of faith. Religious delusion can be compartmentalised and kept apart from scientific endeavour except at certain interfaces (the "when we found the Higgs Boson did it bring us nearer to God?" type of idiocy, for example). Most practising Christians I know are Christians on Sunday mornings but the same as everyone else the rest of the time.   But if you believe in creationism it means that you are far too easily hoodwinked by the evidence-free nonsense that the average believer, who might still least be making a valiant, yet ultimately fruitless, attempt to reconcile evolution with God, might be trying to avoid. If you're hoodwinked into ignoring vast bodies of evidence and harbouring the nonsense of creationism, you can't possibly be possessed of the sound enough mind required to officiate in a Supreme Court. You're a menace to society there, frankly. As for Congress deciding, well Congress is always so infallibly wise, isn't it?