How did Martin Luther weaken the Catholic Church?

Answer 1

The only "power" that the Catholic Church has ever had is the power that God gave it, as the Catholic Church is the Mystical Body of His Son, Our Blessed Lord, Jesus Christ (see Acts 9:105 and 1 Cor 12:12-14). And, as Our Blessed Lord, Himself, said: Jesus answered: My kingdom is not of this world. If my kingdom were of this world, my servants would certainly strive that I should not be delivered to the Jews: but now my kingdom is not from hence. (John 18:36); thus the power of the Catholic Church is not "of this world", and it is divine. To think that Martin Luther could influence God's power in the world is beyond the pale. Martin Luther's teaching certainly affected the number of people who attended the Catholic Church by giving the German princes in northern Germany a chance to be free of Papal influence, they apostatized in droves, thus denying the sacraments and the grace necessary for eternal salvation to thousands of people back then, and uncounted millions since. So, if you look at the Church's "power" as the number of its members, then his teaching allowed the rulers to deprive the common man of his access to Christ's Church in many principalities. This is referred to as the "Peace of Westphalia. See link below the answer box.

Answer 2

Martin Luther never weakened the Catholic Church, if anything he gave it the occcasion to become much stronger. You could say that it was weakened by the number of people who left the Church, dragged out by the German princes, and the English sovereign, and the fact that they, and their heirs were denied many of the means to attain salvation must be laid at Martin Luther's door at the day of judgment. However, the main result (other than loss of members) was a great strengthening of the Church through the Catholic reform:

from A Catholic Dictionary, edited by Donald Attwater, Second edition, revised 1957

The Counter-Reformation is the name given to the Catholic movement of reform and activity which lasted for about one hundred years from the beginning of the Council of Trent (q.v., 1545), and was the belated answer to the threatening confusion and increasing attacks of the previous years. It was the work principally of the Popes St. Pius V and Gregory XIII and the Council itself in the sphere of authority, of SS. Philip Neri and Charles Borromeo in the reform of the clergy and of life, of St. Ignatius and the Jesuits in apostolic activity of St. Francis Xavier in foreign missions, and of St. Teresa in the purely contemplative life which lies behind them all. But these were not the only names nor was it a movement of a few only; the whole Church emerged from the 15th century purified and revivified. On the other hand, it was a reformation rather than a restoration; the unity of western Christendom was destroyed; the Church militant (those still on earth) led by the Company of Jesus adopted offence as the best means of defence and, though she gained as much as she lost in some sense, the Church did not recover the exercise of her former spiritual supremacy in actuality.

from Modern Catholic Dictionary by John A. Hardon, S.J. Doubleday & Co., Inc. Garden City, NY 1980

A period of Catholic revival from 1522 to about 1648, better know as the Catholic Reform. It was an effort to stem the tide of Protestantism by genuine reform within the Catholic Church. There were political movements pressured by civil rules, and ecclesiastical movements carried out by churchmen in an attempt to restore genuine Catholic life by establishing new religious orders such as the Society of Jesus and restoring old orders to their original observances, such as the Carmelites under St. Teresa of Avila (1515-98). The main factors responsible for the Counter Reformation, however, were the papacy and the council of Trent (1545-63). Among church leaders St. Charles Borromeo (1538-84), Archbishop of Milan, enforced the reforms decreed by the council, and St. Francis de Sales of Geneva (1567-1622) spent his best energies in restoring genuine Catholic doctrine and piety. Among civil rulers sponsoring the needed reform were Philip II of Spain (1527-98) and Mary Tudor (1516-58), his wife, in England. Unfortunately this aspect of the reformation led to embitterment between England and Scotland, England and Spain, Poland and Sweden, and to almost two centuries of religious wars. As a result of the Counter Reformation, the Catholic Church became stronger in her institutional structure, more dedicated to the work of evangelization, and more influential in world affairs.