Nope. You missed one. "The People."
And "the people" have very definite opinions that are formed and informed by the church of their choice.
Your assertion is as silly and self serving as the meme that only women can judge women where circumstances are unique to women, or that only veterans are allowed to have any say on what military operations are appropriate.
The people have no role in the operation of the state.
They elect representatives to operate the state.
The people have no direct power other than the vote the ability to sit as a juror.
Nowhere does the constitution allow for any other INSTITUTION to have a role and Santorum's words clearly advocate for that.