I think the answer is that Mormons did it. Same-sex marriage proponents would like to blame the victory on the Church itself, but this is not possible for several reasons.
The Church has no lay clergy. Basic congregations are generally called "wards" and about ten wards make up a "stake" roughly equivalent to a Catholic diocese. All leaders and members at the ward and stake level are unpaid volunteers. None can be considered "employees" of the Mormon church in any way shape or form.
Because of this, Mormons have to make clear distinctions when they are acting as local Church leaders and when they are acting as individuals. Since local Church leaders only serve temporarily in Church leadership callings an action or remark that was appropriate when they were not serving as a temporary Church leader becomes inappropriate when they are. We all have to pay close attention to when and how we say or do things in order to make a clear distinction between church activity and individual activity.
Criticizers of our efforts regarding Proposition 8 like to say that the Church makes a big issue of "plausible deniability" and other distinctions we are told to draw but our motives can also be attributed to our ethics and desire to be accurate and above-board with our Church comments and actions. I have to tread a very thin line on this blog, because I cannot, and should not, infer that I am acting in an official Church capacity concerning anything I write. Since I currently have no Church position, right now, this is comparatively easy for me. It would be suspect for my current Church leader to write these same words on a personal blog.
In order to blame the Church itself for some action you have to show that stake or ward leaders, acting in their official capacity, directed the action. This is pretty hard to do given that the Church has a clear policy about political neutrality and not using Church buildings or resources for efforts like this.
This is not something they trotted out for the Proposition 8 effort. This statement is issued and read every time a general election occurs and is reiterated every time it is remotely relevant to current happenings. Every Member is familiar with it.
It is certainly clear that individual Mormons contributed heavily to the financial coffers of those trying to defeat same-sex marriage. My gut reaction to the dollar amounts was and is, "That's it? There are individual Mormons that could have financed that amount entirely."
The Church appears to have fully disclosed the amounts the institution and its employees gave to the effort although this was not accurately reported by media outlets.
If you are going to evaluate the role the Mormon Church played in this whole affair as opposed to the role of individual members you have got to remember a few basic facts.
1. Mormons, acting as individuals, are used to devoting astronomical amounts of hours to religious and volunteer service.
2. Mormons are old hands at organization, even the young ones, and their ability to organize and coordinate efforts on anything are going to make regular people look inept. They can organize anybody under the table.
3. Mormons view government as legitimate and work within the system to change the system. You are unlikely to find Mormons staging demonstrations, marches or engaging in civil disobedience.
4. Mormons are incredibly cohesive in belief as well as organizational structure. We do not have problems with renegade church leaders or renegade congregations. Our belief system is shared by church membership worldwide.
The reaction of individual Mormons to situations like Proposition 8 is not unusual. You will get this reaction whether it is a social issue or filling sandbags to shore up leaking levees.
"Highly centralized and hierarchical LDS institutional structures, widespread experience with door-to-door proselytizing, disciplined messaging among former missionaries, and extensive social networks that facilitated viral messaging, combined with a religious and cultural tradition that assigns enormous value to obedience to church authorities, service, discipline, and sacrifice to create a potent political force that was no secret to those within the culture."Yes, our top central Church leaders told us this was an issue worthy of our time, devotion and financial means. After that, our reactions as individuals kicked in. Try as you might, you will never be able to vilify, demonize or render illegal the rights of Church leaders to give instruction and advice to its members.