“Pope Pius XI [who] himself fell under the influence of the progressives who were already present in Rome. For we see a distinct difference from the Popes before and after. But nevertheless Pope Pius XI at the same time wrote some magnificent encyclicals. He was not a liberal. “Divini Redemptoris,” his encyclical against Communism was magnificent. So also was his encyclical on Christ the King, which established the feast of Christ The King and proclaimed the Social Kingship of Our Lord Jesus Christ. His encyclical on Christian Education is absolutely admirable and remains today a fundamental document for those who defend Catholic schools.”
“If on the level of doctrine Pope Pius XI was an admirable man, he was weak in the order of practical action. He was easily influenced. It is thus that he was very strongly influenced at the time of the Mexican Civil War and gave the Cristeros, who were in the process of defending the Catholic religion and fighting for Christ the King, the order to have confidence in the government and to put down their arms. As soon as they had put down their arms they were all massacred. This horrifying massacre is still remembered today in Mexico. Pope Pius XI placed confidence in the government who deceived him. Afterwards, he was visibly very upset. He could not imagine how a government, which had promised to treat with honor those who defended their Faith, could have then gone on to massacre them. Thus thousands of Mexicans were killed on account of their Faith.” (Christian Order June-July 2023, page 42)
https://www.thecatholicmonitor.com/2023/06/archbishop-lefebvre-gave-summation-of.html