In the late 1920s, Tiso became one of the party's leaders. When the president of the party Andrej Hlinka traveled in 1926 to the Eucharistic Congress in the United States, he delegated Tiso to represent him in the presidium of the party. In his absence, Tiso led complicated negotiations about an entry of HSĽS into the government. He was successful and thus strengthened his position. In January 1927, he became the Czechoslovak Minister of Health and Physical Education. Since HSĽS previously operated as an opposition party and was not able to fulfill all of its promises, the participation in the government led to the loss of credibility. Tiso again proved his speaker skills and supported the decision to participate in the government. As a minister, Tiso successfully realized several important health service projects in Slovakia. Surprisingly, he refused the government ministry flat, staying in one of Prague monasteries. In October 1929, HSĽS left the government after the Tuka affair. Tiso was more inclined than Hlinka to find compromises with other parties to form alliances, but for a decade after 1929 his initiatives were not successful. In 1930, he became the official vice-president of the party and seemed destined to succeed Hlinka. He spent the 1930s competing for Hlinka's mantle with party radicals, most notably the rightist Karol Sidor – Tuka was in prison for much of this period for treason.