This interesting article from 2004 by Fr. Francois Knittle outlines how St. Pius X exposed the Modernists's tactics for spreading their poison of Modernism, "the synthesis of all heresies":
...we will emphasize what St. Pius X wrote on the tactics of the Modernists. The holy Pope was worried not only about the doctrinal aspects of this question, but also about the progress of this error in minds and hearts.
This article may also help to convey a better understanding of some recently-published articles about Modernism: