McCarthy was so powerful because so many different agencies and individuals took part in McCarthyism-related operations. The public was so frightened by the supposed (and real) threat of communists undermining US security that they supported anyone who seemed to be fighting it
The Charleston. It is associated with white culture's acceptance of Jazz, vaudeville, flappers, and prohibition as the hallmarks of the roaring twenties. It's notably used in popular performances from the era, such as Cole Porter's Anything Goes.
Protestantism was most widespread in northern Europe -- Germany, Scandinavia, England. Switzerland had much Protestantism also in some cantons due to the influence of reformers like Zwingli and Hus.
Proximity to Rome was one factor. The Italian states remained within the Catholic fold.
Political factors also made a difference. In states with a strong central monarch that was Catholic (such as Spain or France), the country was maintained as a Catholic territory. In regions where individual princes had more autonomy--such as Germany--there could be Protestant growth principality by principality. And where there were strong monarchs who wanted independence from Rome's authority, such as England, Protestantism held more sway also.