Current American anti-Muslim bias is being commonly compared to 19th century anti-Catholicism. I think that's sloppy history.
Hateful behavior against belief in general is inexcusable in a society that espouses free speech and religious liberty wherever it happens. And it has happened in every time, whether against free-thinkers, Mormons, Catholics or Jehovah's Witnesses.
While violence against innocent newcomers and non-conformists is always wrong, the fears that underlie those hostilities are often distinctive.
Was the fear of Catholicism itself in the 19th and 20th centuries irrational, based purely on a blind defense of Protestant theology and democratic values?
Surely it was in part. Since the Reformation, Rome had been the symbol of the anti-Christ in many Protestant circles as well as a threat to a young nation whose ethos was democratic and Protestant.
But as the Notre Dame historians point out in their piece in the latest New York Review of Books, those fears were also grounded in concrete foundation. Popes in the latter half of the 19th century railed against egalitarianism and democracy in a frenzied reaction to Europe's revolutionary forces.
Religious liberty wasn't upheld by the Catholic church until the Second Vatican Council. In effect, the teaching of the church held that there was no human right to be anything but Catholic and you could, theoretically ad actually be punished for not subscribing to Catholicism. In Catholic countries, including most recently Franco's Spain, non-Catholics were blatantly discriminated against.
Most virulently anti-Catholics haven't paid much or any attention to those anti-non-Catholic policies that defined Catholicism at least until the Council, but the claims of total supremacy and imperialism of Rome were factors in stirring anxieties among Protestant Americans.
By comparison, no single voice of authority rules Islam, nor have Muslims in general denigrated the integrity of the faith of others (not that Muslims haven't waged war against Christians for a variety of political and faith-based reasons). Islam competes for converts, to be sure, and contains elements of exclusivity, as does every religion, but it hasn't made its central goal declaring that others have no legitimacy. That was, rather, the stuff of Catholic claims to being the "one true Church."
Pope Benedict argues the same today. Iesus Dominus, issued a few years ago, holds fast to the assertion that only the Catholic church is a true "church" and that all others were flawed and unworthy.
In most accounts these days, Catholics are uniformly portrayed as the innocents. While the vast majority of Catholics have been supporters of American values and have never exercised religious bigotry, the church's teachings had for most of our history posed problems for our way of life if acted upon. Thankfully, that is no longer the case. America Muslims are, to that extent, the true innocents, made suspect not by the rulings of a grand leader by the inevitable crimes of some fanatics among them.
During the pope's trip to England, all the politeness and ecclesiastical niceties will probably cover over the anger that the pope's declaration Iesus Dominus (and his call for anti-gay, anti-women's ordination Anglicans to sign on with Rome) has renewed, but it's there under the surface, and to call that anger anti-Catholicism seems to defy the logic of history. Real haughtiness has sometimes created real fears.