I've been introduced to traditionalist Catholicism relatively recently. I study Chemistry and have an interest in academic history, and personally find the living religious tradition of the Catholic Church very enriching.
At the same time, a lot of traditionalist Catholics buy into highly conspiracy-theorist notions- namely, that the modernist forces of Freemasonry and Bolshevism consciously attempted to infiltrate the Church and undermine it from within, and this resulted in the Second Vatican Council.
This seems immediately ridiculous to me, but it's something I hear a lot and if there are any real academics out there with knowledge on the subject, it would be great to hear some reassurance, and get some objective historical opinions on what influenced the shift in the Catholic Church in the mid-20th century.
Like most conspiracy theories, the above is a mixture of facts that are subsequently distorted by a particular lens. As a result, anyone viewing through that lens will perceive any evidence to the contrary with a similar distortion.
Also, as with many topics regarding Catholicism most of the works on the subject start at the conclusion and then go look for evidence to support it. Finding 'some objective historical opinions' is going to be a difficult task.
In my own analysis, if we are going to examine the second half of the 20th century up to Vatican II, I just don't see any evidence to support the conspiracy thesis. Pius XII (pontiff from 1939 to 1958) is more often accused of being overly anti-communist than having a bias towards it. His successor was John XXIII, who called the council in question. In reading his works I don't find Freemason or Bolshevik influence. He died in 1963, after the gathering began but before it concluded. He was followed by Paul VI in that same year. In my opinion, the statements these three pontiffs made on social justice issues don't deviate greatly from Leo XIII's Rerum Novarum, Pius IX's Quadragesimo Anno, the aforementioned John XXIII's Mater et Magistra, or John Paul II's Centesimus Annus.
You will find other interpretations of the record from other sources. I am not sure that you will find a truly objective analysis.
As always, followup questions from OP and others are encouraged.
Clerical land confiscations in Spain occured mainly during the 19th century under a liberalized administration, which surely had its number of freemasons. There were a variety of reasons that had nothing to do with bolshevism, but was pushed by anticlerical sentiments with ties to Freemasonry. The main confiscations under Mendizábal were post the 1936 carlist war, with strong support from the church and the agrarian classes. The church was in possesion of roughly 4 million hectares; 18% of the total arable land, the expression used being «manos muertas» or dead hands for being in a completely immobile market. This land rarely ended up in the hands of a middle class, which at this age would consist mainly of farmers, but was mostly accumulated in the hands of the liberal upper class. The confiscations did not occur all at once, which were dampened with the rise of moderates in 1844, but continued with the reinstatement of progressives from 1854-1856, where the total figure was confiscated. The main effect of the confiscations was a near dismantlement of the Spanish clergy. From 1834 to 1856, the church fell from 3027 convents and 37 orders, to 41 convents and 8 orders.
There was cleary aim to dismantle the church in Spain and many of the main players were masons, although you could attribute it a reaction against carlism or the heavy handed economic liberalism of that age.