"At all times, but particularly in the last two centuries, the Popes, whether individually or together with the College of Bishops, have developed and proposed a moral teaching regarding the many different spheres of human life." - Veritatis Splendor
From the Protestant Reformation to the French Revolution to the Spanish Civil War to now, the Catholic Church has been attacked and persecuted, often explicitly requiring Catholics to renounce, at the very least, Papal authority: teaching on faith and morals.
I was reminded of these things after reading the short biography for today in Magnificat of Bl. Armand Chapt De Rastignac, who had been imprisoned with nineteen other clerics for having refused to take the revolutionaries' anti-papal oath of the Civil Constitution of the Clergy. They were all put to death by a revolutionary mob which stormed the prison.
The Spanish Civil War witnessed the “most extensive and violent persecution of Catholicism in Western history, in some way even more intense than that of the French Revolution.
“More than 6,800 Catholic clergy were slaughtered, including 13 bishops, more than 2,360 monks and friars, 4,172 diocesan priests and seminarians, as well as 283 nuns. Thousands of churches were destroyed. Most of the intense killing occurred in the first six months of the conflict, but by the end of the war about 20% of the nation’s Catholic clergy was dead." - Stanley Payne
Today it is fashionable on the 'popular front' to reject and attack Papal authority and Magisterial teaching, although, pretty much only Islamic countries and China are engaged in outright persecution of Christians.
Within the Church there are progressives who reject papal authority and Magisterial teaching on a host of subjects. Some of the dissenters claim to remain in the Church, but that is questionable. Nonetheless, they claim to be faithful Catholics - those who have not formally left the Roman Catholic Church, though they reject Catholic teaching. Some have left the Church for other denominations more sympathetic to their cause. Others formed their own faith communities, or joined schismatic sects. These have clearly left the Church, and should be given credit for their honesty and integrity in doing so.
Others remain in the Church and claim to be Catholic, though they reject Catholic teaching. Many criticize and condemn Papal-Magisterial teachings. We can recognize them by their errors.
1. Called to salvation through faith in Jesus Christ, "the true light that enlightens everyone" (Jn 1:9), people become "light in the Lord" and "children of light" (Eph 5:8), and are made holy by "obedience to the truth" (1 Pet 1:22).
This obedience is not always easy. As a result of that mysterious original sin, committed at the prompting of Satan, the one who is "a liar and the father of lies" (Jn 8:44), man is constantly tempted to turn his gaze away from the living and true God in order to direct it towards idols (cf. 1 Thes 1:9), exchanging "the truth about God for a lie" (Rom 1:25). Man's capacity to know the truth is also darkened, and his will to submit to it is weakened. Thus, giving himself over to relativism and scepticism (cf. Jn 18:38), he goes off in search of an illusory freedom apart from truth itself. - Veritatis Splendor
O my God, I firmly believe that you are one God in three divine persons, Father, Son and Holy Spirit. I believe that your divine Son became man and died for our sins, and that he will come to judge the living and the dead. I believe these and all the truths which the holy Catholic Church teaches, because you have revealed them, and in revealing them you can neither deceive nor be deceived. Amen