Pope Paul VI created him Cardinal Priest of "S. Pio X alla Balduina" in the consistory of April 28, 1969. During the 1971 Synod of Bishops in Vatican City, Dearden suggested that the sociological and psychological aspects of the priesthood be investigated. Following the outbreak of the Watergate scandal in 1973, Dearden issued a pastoral letter in which he remarked, "These are difficult days for the country we love," and asked Catholics to observe the first three Fridays in November as days of prayer, penance and fasting in light of the nation's political turmoil. He suffered a serious heart attack in April 1977.