Since its transition to democracy more than 25 years ago, Spain's wall between church and state has been a bit porous. Despite ratifying a constitution in 1979 that prohibited a state religion, the country's dominant Roman Catholic church has continued to enjoy preferential treatment from the government.
But now, José Luis Rodríguez Zapatero's Socialist government is working to shore up the barrier between church and state.
Last week, his administration announced plans for a "road map" that would treat all religions equally under the law, remove religious symbols from public spaces, and end compulsory religious instruction in public schools.
Most controversially, it would divest the Catholic Church of the economic and social privileges it has enjoyed for centuries. Some say the Socialists are trying to strip Spain of its special heritage. Others see evidence of a natural evolution towards full democracy in a secular state.
In a country whose constitution guarantees freedom of religious expression and forbids official sponsorship of any particular faith, such a change might seem unremarkable.
But Spain's constitutional history is unusual, fraught with compromises that made democracy here take a form different from the one promoted by Thomas Jefferson.
Instead of divorcing church and state, the authors of the Spanish constitution opted for a handshake between the two institutions. After all, the last - and only other - attempt to radically alter church-state relations was a leading cause of the country's 1936 civil war.
Less than a week after the constitution was put into effect in 1979, for example, the Spanish state signed a set of agreements with the Holy See that in effect continued the Catholic Church's privileged legal and economic status.
Victorino Mayoral, a socialist member of congress and president of the Cives Foundation, an organization dedicated to establishing a lay government, says those accords were signed "to resolve political problems" and ensure stability.
Indeed, though signed after the constitution, the accords had actually been negotiated and agreed upon well before. The result was two sets of rules governing state-church relations. Spain thus became, notes Mr. Mayoral, "a secular society, on the one hand, but remained a Catholic state, on the other."
Last Friday, first Vice President María Teresa Fernández de la Vega made clear that the government intended to further establish Spain as a genuinely secular state.
That effort is renewing debate about Spanish national identity - and the role of church funding. Last year, the church received about 3.5 billion euros ($4.3 billion) of state money to support its ecclesiastical, educational, social, and cultural endeavors.
Supporters of the Socialist proposal, like Pedro Cruz Villalón, a professor of constitutional law at Madrid's Autonomous University, call the subsidies "unjustified." It's an opinion shared by Mayoral, who says that in a "democratic society, where church and state are separate, political advantages are unacceptable because they harm the development of all liberties."
Not surprisingly, the Catholic Church opposes the measure. A spokesman for the Spanish Episcopal Conference, Juan Antonio Martínez Camino, told the newspaper El País last week that the state's traditional support of the church "is important, has its place, has nothing to do with privilege. We have a right to it, and it's done in many other European countries, like Germany or Italy."
Although Martínez insisted that the Catholic Church "never has, nor will it now, organize political demonstrations," the Episcopal Conference has nevertheless encouraged individual Spanish citizens to make their opinions known.
Since that announcement, the Conference - perhaps mindful of the importance of good relations with the Zapatero government - has refused to make any further declarations.
Local newspapers, however, have cited calls by unnamed bishops upon faithful Catholics to join forces against the Socialists' "anti-Christian secularism."
And some of the country's more conservative newspapers have likewise taken up the call. An unsigned editorial in El Mundo, for example, recently declared that Zapatero's attempt to "erase the past" ignores the country's unique religious heritage and warned that it will meet with ferocious resistance.
Zapatero has recently played down the road map, saying that his party will not "denounce" or fundamentally change the 1979 accords.
Respecting the "free exercise of conscience" in an increasingly diverse Spain is, according to Mayoral, the central challenge facing the government. Compared with the country in 1936, today's Spain is a wholly different place.
"The church has long had a monopoly on morality," says Mayoral, "but now there is not just one religion, but a plurality of faiths." He notes that today less than 30 percent of Spaniards identify themselves as practicing Catholics, while roughly 70 percent did 25 years ago.
The country's religious composition now is also far more diverse: There are an estimated 1,000,000 Muslims and more than 2,000,000 Protestants living within Spain's borders.
Even since its 1979 constitution, Spain has not consistently tolerated religious diversity, Although Cruz Villalón asserts that the new measure is not "a secular crusade," it is clear that Spain is facing the urgent question of whether it is ready to break with its past and take concrete steps to ensure genuine religious freedom.