What are the limitations of the Roman Catholic Church in determining the validity of a marriage?

To be certain that these limitations are now deeply rooted, one need only recall the comment made by Lord Moulton in Despatie v. Tremblay (1921), 47 B.R. 305 (P.C.), with respect to the law as it stood at the time of the coming into force of the Quebec Act (U.K.), 14 Geo. 3, c. 83: The law did not interfere in any way with the jurisdiction of any ecclesiastical courts of the Roman Catholic religion over the members of that communion so far as questions of conscience were concerned. But it gave to them no civil operation. Whether the persons affected chose to recognize those decrees or not was a matter of individual choice which might, or might not, affect their continuance as members of that religious communion. But that was a matter which concerned themselves alone. [p. 316] The Law Lords accordingly refused to apply the religious rule to determine the validity of the marriage in issue.