From an Internet Discussion List
The labors of the First Vatican Council, including its definition of Papal Infallibility, came in response to the problems of secularism and rationalism that plagued the Church for centuries before Columbus discovered America. The Council was called to give Catholics a uniform understanding of the Church as a perfect and independent society, so that the Church might assert Itself against the encroachments of secular governments and rationalist ideologies. The very basis of Christendom was threatened by attempts to secularize even such fundamental things as marriage and education. Pope Pius IX's 1864 Syllabus of Errors is a good summary of the problems the Church saw Itself facing.
But, again, these problems had been growing for hundreds of years:
In the early 13th century Pope Innocent III presided powerfully over a Europe relatively united by its Catholic Faith. Eight or ninety years later, the Pontificate of Pope Boniface VIII would mark the beginning of a steady loss of Catholic influence over the affairs of Europe. King Philip IV, first to staff his bureaucracy with secular lawyers in preference to Catholic clerics, contested the Pope's right to collect taxes from the French Church, sent his agents to capture Boniface (who died days later), and forced the beginning of the Avignon captivity of the Papacy in the early 14th century.
The 15th and 16th centuries brought not only the Reformation and non-Catholic States, but witnessed the "most Christian King" of France allying himself with the Moslems against the "most Catholic King" of Spain. When the Thirty Years War concluded 1648 at Westphalia, not only was the Church denied its traditional role as arbiter and supervisor of the peace, but it was forced to cede properties and representatives at the Imperial court. The next centuries brought the "Enlightenment," the French Revolution, the Terror and the spread of anticlerical sentiment and violence throughout Europe and the Americas.
The beginning of the 19th century saw Pope Pius VII forced to sign a concordat with Napoleon, giving up property, recognizing the revolutionary bishops, and allowing Napoleon to designate them as bishops in place of the non-juring Catholics. Soon Napoleon would ignore the Pope and crown himself Emperor in Notre Dame, invade the Papal States, and carry Pius VII away to France. Mid-century came German unification, and then the beginnings of an Italian State under the House of Savoy threatening the territory of the Pope. Invariably, all of these movements had an ideological anticlerical dimension to them. Often they received the support of high political and economic leaders.
There was opposition to the definition of Papal Infallibility as much in Europe as in America, often for the same reason: Catholics on both continents lived in societies dominated by militant non-Catholics. Legal and illegal organizations persecuted Catholics, and made them out to be subversives subject to a foreign power -- It would not help if that foreign power declared itself Infallible! And they may have been right in their reserve. While there may not be a direct causal connection, it gives pause to realize that Infallibility was defined on July 18, 1870, and Rome was captured by Victor Emmanuel on September 20th. Besides, few Catholics had questioned Pope Pius' infallible proclamation of the Immaculate Conception just fifteen years before the council.
Americans (among others of course) at the Seventh Council of Baltimore in 1849 had indeed petitioned Pope Pius to declare the doctrine. Mary, under the title of her Immaculate Conception, had been our national Patroness since the Sixth provincial Council of Baltimore in 1846. Of the 46 U.S. prelates eligible to vote at Vatican I, 21 initially opposed defining Infallibility, together with 120 bishops from other nations. When the declaration of the dogma came to a vote, one of only two votes against it came from an American -- the Bishop of Little Rock, who is said to have been afraid to return home to a welcome by the Klan. When Leo XIII issued Testem benevolentiae in 1899, he clearly indicated that the source of his concerns stemmed from a foreign (French) translation of Isaac Hecker's work, and that it was not clear to him that the errors were accepted by the American clergy. Very likely, Pope Leo was also influenced by the widespread European speculation the mistranslation had caused. The encyclical is relatively brief, and is worth reading by those interested in the controversy. There is a summary in The Catholic Encyclopedia.
The Baltimore Catechism (1885) did not raise Baptism of Desire to the status of a defined proposition of the Faith -- that had been done over three hundred years earlier at the Council of Trent. The doctrine was discussed in the Decree on Justification, Session VI, 3 January 1547, Chapter IV (Denzinger 796/1524). It is cited in "anathema" form by the Session VII, 3 March 1547, Canon 4 (Denzinger 847/1604). It is mentioned in the Tridentine Catechism, pars II, caput II, No. 36. But even those teachings before Trent about Baptism of Desire that might be called speculative come from very well accepted Catholic authorities including Ambrose, Augustine, Aquinas, and Popes Innocent II and III. Had Vatican I been left to its business in peace, we might have heard more from Pope Pius IX, who, while holding strictly to the necessity of belonging to the Church, admitted the possibility that those in "invincible ignorance of the true religion" might attain eternal life by devotedly following the principles of the natural law (Cf. Quanto conficiamur moerore, Denzinger 1677/2865). Later revisions to The Baltimore Catechism (c.1940) seem to incorporate this thinking (Q.323)