stylistic:tone
Internal politics

Piłsudski's coup entailed sweeping limitations on parliamentary government, as his Sanation regime (1926–1939), at times employing authoritarian methods, sought to curb perceived corruption and incompetence of the parliament rule, and in Piłsudski's words, restore "moral health" to public life (hence the name of his faction, "Sanation", which could be understood as "moral purification"). From 1928, the Sanation authorities were represented by the Non-partisan Bloc for Cooperation with the Government (BBWR). Popular support and an effective propaganda apparatus allowed Piłsudski to maintain his authoritarian powers, which could not be overruled either by the president, who was appointed by Piłsudski, or by the Sejm. The powers of the Sejm were curtailed by constitutional amendments that were introduced soon after the coup, on 2 August 1926. From 1926 to 1930, Piłsudski relied chiefly on propaganda to weaken the influence of opposition leaders.

The culmination of his dictatorial and supralegal policies came in the 1930s, with the imprisonment and trial of political opponents (the Brest trials) on the eve of the 1930 Polish legislative election and with the 1934 establishment of the Bereza Kartuska Detention Camp for political prisoners in present-day Biaroza, where some prisoners were brutally mistreated. After the BBWR's 1930 victory, Piłsudski allowed most internal matters to be decided by his colonels while he concentrated on military and foreign affairs. His treatment of political opponents and their 1930 arrest and imprisonment was internationally condemned and the events damaged Poland's reputation.

Piłsudski became increasingly disillusioned with democracy in Poland. His intemperate public utterances (he called the Sejm a "prostitute") and his sending of 90 armed officers into the Sejm building in response to an impending vote of no-confidence caused concern in contemporary and modern observers who have seen his actions as setting precedents for authoritarian responses to political challenges. He sought to transform the parliamentary system into a presidential system; however, he opposed the introduction of totalitarianism. The adoption of a new Polish constitution in April 1935 was tailored by Piłsudski's supporters to his specifications, providing for a strong presidency; but the April Constitution served Poland until World War II, and carried its Government in Exile until the end of the war and beyond. Piłsudski's government depended more on his charismatic authority than on rational-legal authority. None of his followers could claim to be his legitimate heir, and after his death the Sanation structure would quickly fracture, returning Poland to the pre-Piłsudski era of parliamentary political contention.

Piłsudski's regime began a period of national stabilization and of improvement in the situation of ethnic minorities, which formed about a third of the Second Republic's population. Piłsudski replaced the National Democrats ' " ethnic-assimilation " with a "state-assimilation" policy: citizens were judged not by their ethnicity but by their loyalty to the state. Widely recognized for his opposition to the National Democrats' anti-Semitic policies, he extended his policy of "state-assimilation" to Polish Jews. The years 1926 to 1935 and Piłsudski himself were favorably viewed by many Polish Jews whose situation improved especially under Piłsudski-appointed Prime Minister Kazimierz Bartel. Many Jews saw Piłsudski as their only hope for restraining antisemitic currents in Poland and for maintaining public order; he was seen as a guarantor of stability and a friend of the Jewish people, who voted for him and actively participated in his political bloc. Piłsudski's death in 1935 brought a deterioration in the quality of life of Poland's Jews.

During the 1930s, a combination of developments, from the Great Depression to the vicious spiral of OUN terrorist attacks and government pacifications, caused government relations with the national minorities to deteriorate. Unrest among national minorities was also related to foreign policy. Troubles followed repressions in the largely-Ukrainian eastern Galicia, where nearly 1,800 persons were arrested. Tension also arose between the government and Poland's German minority, particularly in Upper Silesia. The government did not yield to calls for antisemitic measures, but the Jews (8.6% of Poland's population) grew discontented for economic reasons that were connected with the Depression. By the end of Piłsudski's life, his government's relations with national minorities were increasingly problematic.

In the military sphere, Piłsudski was praised for his plan at the Battle of Warsaw in 1920, but was criticized for subsequently concentrating on personnel management and neglecting modernization of military strategy and equipment. According to his detractors, his experiences in World War I and the Polish-Soviet War led him to over-estimate the importance of cavalry, and to neglect the development of armor and air forces. His supporters, on the other hand, contend that, particularly from the late 1920s, he supported the development of these military branches. Modern historians concluded that the limitations on Poland's military modernization in this period was less doctrinal than financial.