In the years right after 1918, several Magyar political formations appeared, some calling for integration into the just-unified Romanian state, others not recognising the new realities settled through the Alba Iulia Resolution.

After Hitler came to power in Germany and Miklós Horthy's régime sharpened its revisionist rhetoric, the party leadership more often than not took anti-Romanian stances, following the Budapest government's line.

While the CNM hedged its bets, hoping for a change in the situation through the signing of a peace treaty, the PNDM-S decided to collaborate with the authorities and to participate in the November 1919 election, in which it received 8 seats in the Assembly of Deputies.

On June 5 of that year, a petty bourgeois group meeting at Huedin formed the Hungarian People's Party (Partidul Popular Maghiar), with Ludovic Albert as president.

It was led by the old Magyar aristocracy and sustained by solid banking institutions, a network of cooperatives, the church and a number of cultural organisations, and a sizeable press with a wide area of distribution.

István Ugron, who favoured an exclusive collaboration with the PNL, broke the "Ciucea Pact" on February 1, 1926, yielding the post of president to count György Bethlen.

Opposition by the democratic circles in the PM, grouped around Miklós Krenner and the newspaper Keleti Újság ("Ştirile vestului" or "News of the West"), was powerfully manifested at the Gheorgheni Congress of February 26, 1926.

At the last PM Congress, which took place in Târgu Mureş in November 1937, it was asserted that the Romanian government was promoting a policy of assimilation toward minorities, and of violating their rights and liberties of expression.

Dissolved, along with all other political parties extant in Romania, on March 30, 1938, the PM continued to exist under the name of the Magyar Community (Comunitatea Maghiară), which joined the National Renaissance Front in January 1939.

After the Second Vienna Award of August 30, 1940, almost all PM leaders remained on territory ceded to Hungary, holding various political and administrative functions, and promoting a policy of harsh repression against the Romanian inhabitants of that land.