No more Protestants on the Supreme Court -- should we care?

With Justice Stevens retiring, should we care that there might not be any Protestants on the Supreme Court?  According to Rick -- via Nina Totenberg -- the more relevant divide is "religious-secular."  Over at the Law Religion Ethics blog, I've posed some questions in response (and opened comments).  Put simply, does the particular religious identity of a Supreme Court justice matter?  Should it?