This past week, Tim Kaine, the Democratic vice-presidential candidate, gave the keynote address at the national dinner for Human Rights Campaign, an influential LGBT advocacy group, in Washington, D.C. In it, he said that the Catholic Church was bound to eventually change her teaching on same-sex marriage.

Kaine stated: “I think it’s going to change because my church also teaches me about a Creator who, in the first chapter of Genesis, surveyed the entire world, including mankind, and said, ‘It is very good,’” and further cited His Holiness, Pope Francis’ “who am I to judge,” in referencing homosexuality.

Kaine is a Roman Catholic who is an active parishioner at St. Elizabeth Catholic Church in the Diocese of Richmond, Va.. Yet, like many Catholic politicians, opposes the Church’s teachings on several public policy issues. There are several issues with his understanding of the consistent ethic of life. Like many Catholic politicians, Kaine states that he is “personally opposed” to abortion. At the same time, he received a 100-percent rating in 2016 from the Planned Parenthood Action Fund and a perfect rating in 2015 from NARAL Pro-Choice America.

It has also been reported that Kaine is favor of overturning overturning the Hyde Amendment, which forbids public monies to fund abortion and has voted against bringing a 20-week abortion ban to a vote on the Senate floor. It doesn’t sound like he is “opposed” in any way to abortion.

In terms of the death penality, Kaine voices personal opposition, but as Governor of Virginia, his term saw 11 executions with only one commuted death sentence.

The Church’s teaching on same-sex marriage cannot change because her teaching is based not only on ecclesiastical law, but also on natural law.

God, who created man out of love, also calls him to love the fundamental and innate vocation of every human being. Since God created man and woman, their mutual love becomes an image of the absolute and unfailing love with which God loves man. It is good, very good, in the Creator’s eyes. And this love which God blesses is intended to be fruitful and to be realized in the common work of watching over creation.

Scripture affirms that man and woman were created for one another. The Lord himself shows that this signifies an unbreakable union of their two lives by recalling what the plan of the Creator had been “in the beginning.”

Thus, marriage is known as a permanent life commitment between a man and a woman, as sacrament of unity between the two, for the mutual support of each other and the procreation of children. It is not possible for the Church to “evolve” her definition of marriage unless we completely redefine terms that are coming from the two fonts of divine revelation: sacred Scripture and sacred tradition.

In addition, a recognition of same-sex marriage would have to redefine what is meant by natural law.

Kaine needs to realize that recognition of same-sex marriages is more than just a matter of having the Church change her mind. It would affect our entire understanding of the sacraments and natural law. While affirming the dignity of every human being as having been created in the image and likeness of God, the Church cannot recognize same-sex marriage as a sacrament. It’s more than a matter of fairness or open-mindedness. It is a theological and sacramental matter.