There will be, if Alito is confirmed. This is an extraordinary development. It was, let's recall, only forty-five years ago that JFK's Catholicism was a major issue in a presidential campaign. As Ken Kersch and Philip Hamburger have shown, anti-Catholic sentiment played a large role in the development of modern establishment clause jurisprudence (in part through the influence of that old KKKer, Hugo Black). The leading separationist group after WWII was known as Protestants [now, Americans] United for the Separation of Church and State.
We can rejoice that Catholics are now such an accepted part of the American scene that it will hardly raise any eyebrows that a fifth Catholic has been nominated to the Supreme Court (joining, of course, two Jews). I'll leave it to the sociologists to explain this phenomenom in detail, but I'd venture that it's not simply a result of more enlightenment on the part of non-Catholic Americans, but also that Post-Vatican II, the Catholic Church is less foreign, both in prayer (in that mass is now in English), sociologically (because Catholics no longer differ that much from other Americans in where they send their kids to school and how many children they have), and in terms of ideas (e.g., the Church's renouncement of anti-Jewish theology; compare the 19th century Edgardo Mortara case). In short, as with American Jews and other groups, a story of both declining prejudice and assimilation.