PINU was created by Miguel Andonie Fernández as a democratic, moderate left-wing alternative to the two major parties and the military regime.

In the presidential contest the same day, Enrique Aguilar Cerrato, the party's nominee, placed fourth, taking 1.54% of the vote.

In the presidential contest the same day, Enrique Aguilar Cerrato, the party's nominee, placed fourth, taking 1.54% of the vote.

[4] At Congressional elections held 30 November 1985, PINU won three seats in the 134-member assembly, marking the highest level of representation achieved by the party since its inception.

In the presidential contest the same day, Olban Francisco Valladares Ordóñez, the party's nominee, placed third, winning 2.1% of the vote.

In Congressional elections taking place on 27 November 2009, PINU won three seats in Congress, earning 6.43% of the total vote.

[7] In Congressional elections taking place on 24 November 2017, PINU won one seat in Congress, earning 1.83% of the total vote, marking a significant decrease in support.