It doesn’t take a weatherman to tell which way public opinion blows. The huge uptick of support for same-sex marriage has been described as swift and broad, to which we can add, in all likelihood, lasting.
In my view, every time the defenders of the traditional view of marriage speak in public on behalf of a ban, they lose the support of neutral third parties. The problem is that they are trying to tell other people how they should lead their own lives, and are using the power of the state to do it. Their justifications are far from compelling. They talk about the need for procreation in marriage, though many straight married couples use contraceptives. They talk about the risks to parenting, when there is no evidence that suggests that gay and lesbian couples are worse parents, especially when compared to dysfunctional couples in traditional marriages or single parents of limited financial means. Their arguments against same-sex marriage thus fall flat to modern ears, so that the basic support for same-sex marriage only grows.