Founded in 1926, the UNP registered its first electoral gains in 1928, an ally of the National Peasants' Party. Its team contested all the elections of the following nine years, often against other Ukrainians or Rusyns, and almost always in alliance with mainstream parties. Around 1933, its anti-communism made it prone to infiltration by Nazi agents. Its final appearance was during the 1937 race, when it won its last seat in Parliament in cartel with the National Liberal Party. Like all other Romanian parties, the UNP was banned, in early 1938, by the National Renaissance Front. Zalozetsky-Sas and other former UNP leaders served as Ukrainian representatives within the Front before the Soviet occupation of 1940.