Three decades ago most people would have scoffed at the idea. A century ago, the vast majority would have been perplexed that the proposition was even raised. Almost no one, until fairly recently, accepted the notion that gay marriage was a human right.

How, it would have been asked, could something which had not even existed until almost the day before yesterday be considered a right? That would be like calling the ownership of a cellphone a right.

But come to think of it, some folks are indeed calling cellphone ownership a right. Moreover, nowadays, according to some polls, nearly half of all Americans have decided that homosexual marriages are on a par with freedom of speech and freedom of religion.

What has happened here? How can our moral judgments have changed so rapidly? Have people, in fact, discovered a new civil right? Or is it merely that they have been sensitized in ways their ancestors were not?

One of my specialties is the sociology of morality; hence I find it fascinating to observe a moral right being created right before my eyes. Many people think of morality as eternal and never changing, but the evidence that much of it is socially constructed is difficult to deny. The gay rights crusade is a case in point.

Consider how this new moral entitlement has risen from nowhere to dominate many political discussions. The steps in this evolution are classic. They provide a vivid example of moral entrepreneurship at its creative best.

The first step to establishing a moral right is to affirm it. People who want a novel entitlement to be socially accepted must begin by asserting it. They must proclaim loudly, and energetically, that it is an eternal verity. It does not matter whether anyone has previously entertained the idea as long as they insist it is a universal truth.

Next, they must demonize the opposition. Those who disagree with them must be portrayed as the essence of evil. Only their vile, mean-spirited natures could prompt them to deny so valid a claim. If need be, they must be punished to provide an example of what happens to villains.

As part of this process, the pain and suffering endured by the purported victims must be highlighted and driven home. In the case of gay marriage, individual couples whose love has been crushed by the bigotry of the mob need to be offered up as object lessons as to why we need this new right.

In moral negotiations — for that is what these are — the objective is to elicit sympathy for one’s own side, while simultaneously arousing loathing for the other. The goal is to convert as many as people as possible to one’s own viewpoint.

If all goes well, a bandwagon effect will have been fashioned. The fact that one’s allies are increasing in number will then influence the uncommitted to join what seems to be the winning side. As a result, one’s own position will become dominant and the new right will have been established.

President Barack Obama’s coming out of the closet to support gay marriage was part of this momentum-building process. He, and those who agree with him, hope that it will nail down a majority so sizeable that henceforth no one will consider supporting their competitors.

Because rights exist when and only when overwhelming numbers of people subscribe to them, in having swung popular opinion in their favor, the gay marriage advocates will have achieved their objective. What had not been a right will, by virtue of their political efforts, have become one.

That said, the game is still in progress. It is in the interest of the pro-gay marriage faction to portray their victory as inevitable, but it is not. The perception that it is, is itself part of the process of trying to recruit as many people as possible to their side.

Melvyn L. Fein Ph.D. is professor of Sociology at Kennesaw State University.