Gordon Satterly, 61, from Michigan (L) kisses his husband Richard Brand, 53, from Texas, at the International Gay Rodeo Association's Rodeo In the Rock party in Little Rock, Arkansas, United States April 24, 2015. (Lucy Nicholson/Reuters)

José Luis Rodríguez Zapatero was prime minister of Spain from 2004 to 2011.

Next month will mark the 10th anniversary of the passing of the act legalizing marriage between same-sex couples in Spain. My country was the third in the world to take this step, after Belgium and the Netherlands. This month, Ireland became the first country in the world to legalize gay marriage via popular vote.

I know how so many people in Ireland feel right now. When the parliament passed Spain’s same-sex marriage law on June 30, 2005, I said that our country would from that moment on be a fairer place. And I honestly believe that this has been the case. Our Constitutional Court ultimately upheld the act, and today all parties in the Spanish parliament accept legal gay marriage as a matter of course, as do most people in my country.

It is important to note that only a few decades ago, Spain was an officially Roman Catholic country where the law defined homosexuality as “antisocial” and stipulated that gay people be confined to rehabilitation centers. Most young Spaniards likely are unaware that this was the case as recently as January 1979, when the laws making homosexuality a criminal offense were repealed. This is understandable given that, according to a 2013 survey by the Pew Research Center, Spain is now among the most tolerant countries in the world toward homosexuality; 88 percent of Spanish people consider homosexuality to be socially acceptable, compared with 60 percent of Americans. As Ireland’s vote suggests, Western European countries are generally the most tolerant toward homosexuality, while a connection can be observed between societies in which religion tends to hold a central position and greater intolerance in this area.

As a citizen of a democracy that is still young, allow me to show how proud I am of the level to which Spain accepts homosexuality and to recognize how valuable this acceptance is. Because I do not believe that tolerance can be divided. There is no middle ground between tolerance and intolerance. It is quite often the case that those who reject or are wary of homosexuals feel the same way to some extent about immigrants, those who practice other religions and perhaps women as well. And those who are comfortable with homosexuals tend to be comfortable with other groups. Phobias seem to be contagious, as is tolerance.

Therefore, a society that is tolerant of homosexuals is highly likely to be, quite simply, a tolerant society. And this is the situation in my country, where there are low levels of xenophobia, even as high numbers of immigrants have arrived from different regions of the world over the past few decades; where there is a positive climate of religious tolerance; and where clear progress has been made in the struggle for effective equality between men and women, although there is still some way to go.

I belong to the generation of Spaniards who reached adulthood at the historic moment when my country became a democracy. Many of us learned then to admire the great democracies of the world, such as the United States. For that reason, I would expect that in a country where public freedoms developed so robustly, based in part on an affirmation of religious freedom, this freedom wouldn’t be invoked in some states to enact intolerant and discriminatory laws.

I admire the work of America’s Founding Fathers because I believe they envisioned civil happiness, which is the happiness found in living together, with each person’s enjoyment of freedom linked to an awareness of that same enjoyment by others — not a need to impose one’s beliefs on other people.