The nation is abuzz with the visit of Pope Francis. There is, of course, a lot that could be discussed with the coming of the Pope, but for education it is a good time to remember the crucial importance of freedom. After all, for much of our history the biggest fights in education were over the public schools’ inability to accommodate Roman Catholics.

From the earliest advocacy of public schooling, arguably the primary goal has been to unite diverse people. As Founding Father Benjamin Rush put it in his Thoughts upon the Mode of Education Proper in a Republic, “Our schools of learning, by producing one general and uniform system of education, will render the mass of the people more homogeneous and thereby fit them more easily for uniform and peaceable government.”

Of course, there is a fundamental problem with this: diverse people will almost certainly want diverse things out of education, so conflict – and suppressing of politically weak minorities to end it – is inevitable.

For much of American history, there was no bigger flashpoint than religion.

Notably, the first religious disputes over “common schools” were not between Catholics and Protestants, but among Protestants. In the Massachusetts of common schools “father” Horace Mann, many orthodox Protestants took issue with the public schools that were to teach “nonsectarian” Christianity, a lowest-common-denominator Protestantism that, among many things, appeared to be Unitarian – Mann’s denomination. It is likely that Mann just wanted to avoid doctrines that would spur theological disputes, but even that proved impossible, with the absence of such doctrines also appearing sectarian.

Even with this divide among Protestants, it was the arrival of large numbers of Roman Catholics that really amped up religious combat over the nascent public schools. Driven by ancient European animosities and fears of Church authority being incompatible with democracy, defenders fought hard to keep a distinctly Protestant cast to the common schools, including reading only from the King James version of the Bible and using textbooks that at times featured content hostile to Catholicism.

Earlier, I used the term “combat” to describe the fights between Catholics and Protestants over the schools. Usually that only applied metaphorically, but not always, most shockingly with the Philadelphia Bible Riots, which were touched off by an ongoing conflict over whose version of the Bible could be used in the public schools. By the end of two waves of street-level warfare hundreds of people had been injured, tens killed, and millions of dollars of property damage inflicted.

Of course, there was not always conflict. Some districts found ways to work with Catholics, and many Catholics accepted the status quo. Still, a huge way by which peace was achieved was Catholics withdrawing from the public schools and starting their own institutions. But that meant paying twice for education: once for hostile public schools, a second time for schools that taught their religion and shared their values. It was an inherently unequal, unfair system.

Today, Catholic schools are not nearly as numerous as they were at their peak in 1965, when roughly 12 percent of all school-aged children – about 5.5 million kids – attended them. There are myriad reasons for this, including Catholics’ full integration into American society, movement from urban areas to suburbs, and the huge decline in school staffing by clergy and sisters who kept personnel costs at rock-bottom levels. But it is also clear that it is very hard to get people to pay for private schooling when there are free public schools, even if the free education is not as good. Making matters worse are charter schools, schools of choice that many parents perceive as private schools but which are, in fact, free public institutions.

Troublingly, it is perhaps now more than ever that we need school choice, because Americans are more diverse than ever.

There continues to be major religious diversity, and options outside of public schools appear to be especially in demand among evangelical Protestants who see public institutions as hopelessly devoid of God. There are also Lutheran, Episcopalian, Quaker, and other religious schools in demand by people who either want specific religious tenets taught to their children, or just access to schools with strong and coherent moral anchors. And then there are public schools where many atheists or members of minority religions perceive too much religious influence.

Of course, diversity doesn’t stop with religion…at all As you can see on Cato’s Public Schooling Battle Map, Americans have diverse and conflicting views on moral issues apart from religion; on what should be taught in history classes; on how freely students should be able to express themselves in school; and as recent headlines makes clear, on how strict discipline policies should be. And, of course, there are ongoing fights over how to treat racial and ethnic groups that have suffered far worse discrimination that Roman Catholics.

All of this – the incessant forced conflict and the subjugation of the politically weak often needed to end it – is utterly inconsistent with the individual liberty that is supposed to be at the core of American life. Perhaps the arrival of Pope Francis can spur us to remember how painfully that has played out in the past.