The famous Syllabus of Errors by Bl. Pope Pius IX condemns, among others, that:
In the present day it is no longer expedient that the Catholic religion should be held as the only religion of the State, to the exclusion of all other forms of worship.—Allocution "Nemo vestrum," July 26, 1855.
Hence it has been wisely decided by law, in some Catholic countries, that persons coming to reside therein shall enjoy the public exercise of their own peculiar worship.—Allocution "Acerbissimum," Sept. 27, 1852. - The Syllabus of Pius IX
Therefore, it would seem that Pius IX orders that all religions bar Catholicism are to be declared illegal by the State.
I am confused. While I don’t know about any official modern document of the Church regarding this issue, the Church really, really doesn’t seem to hold such a position nowadays. Instead, St. Pope John Paul II and Pope Francis have both participated in interfaith prayers for peace alongside not only non-Catholic Christians, but also leaders of heathen religions. This seems to me to hardly reconcile with the above condemnations of Pius IX.
My explanation, up to now, was that the Syllabus has never been officially declared infallible and the current activities of modern Popes like the aforementioned prayer for peace and others prove that the Church has shifted its position on this subject and therefore, these points of the Syllabus are no longer in force.
Am I right? At least, they were in force in the beginning of the XX century, because the Catholic Encyclopedia wrote that:
Even should the condemnation of many propositions not possess that unchangeableness peculiar to infallible decisions, nevertheless the binding force of the condemnation in regard to all the propositions is beyond doubt. For the Syllabus, as appears from the official communication of Cardinal Antonelli, is a decision given by the pope speaking as universal teacher and judge to Catholics the world over. All Catholics, therefore, are bound to accept the Syllabus. Exteriorly they may neither in word nor in writing oppose its contents; they must also assent to it interiorly. - The syllabus of Pius IX
Some questions force themselves into my mind:
Are condemnations 77-78 from the Syllabus of Error still in force, binding all Catholics to adhere to them and agree with them?
Does this mean that the Church wants worship of non-Christian and non-Catholic Christian religions banned by the State?
How to reconcile numerous ecumenical and interfaith activities held by modern popes, like the interfaith prayers for peace with these condemnations?