Long-time GetReligion readers, do you remember that typology that a wise, older priest -- a veteran of life inside the DC Beltway -- gave me a few years ago that proposed that there are essentially four kinds of American Catholic voters?

It went something like this (amended a bit):

* Ex-Catholics. Solid for the Democrats. GOP has no chance (unless these ex-Catholics have converted, as many have, to conservative Protestant flocks)

* Cultural Catholics who may go to church a few times a year. This may be an undecided voter -- check out that classic Atlantic Monthly tribes of American religion piece -- depending on what is happening with the economy, foreign policy, etc. Leans to Democrats.

* Sunday-morning American Catholics. This voter is a regular in the pew and may even play some leadership role in the parish. This is the Catholic voter that is really up for grabs, the true swing voter that the candidates are after.

* The “sweats the details” Catholic who goes to confession. Is active in the full sacramental life of the parish and almost always backs the Vatican on matters of faith and practice. This is where the GOP has made its big gains in recent decades, but this is a very small slice of the American Catholic pie.

Now, I know that this will be hard, but try to strip the political content out of that typology (note, if you will, that I did not click the "politics" box in the categories list). Focus on the issues of religious discipline and practice of the ancient sacraments of an ancient church.

Think about the sacrament of marriage.