Among its leading members are former Prime Minister Massimo D'Alema, former PD secretaries Pier Luigi Bersani and Guglielmo Epifani, and Arturo Scotto.

The name refers to article 1 of the Italian Constitution that defines Italy as "a democratic republic based on labour" (una Repubblica democratica, fondata sul lavoro) and affirms popular sovereignty.

A group of SI dissidents, led by Arturo Scotto (once a member of the DS too) and Massimiliano Smeriglio (who, like most SI members, hailed from the Communist Refoundation Party, PRC), were interested in joining the Progressive Camp (CP), a would-be and never established political party launched by Giuliano Pisapia,[18][19] but they finally decided to join with the PD splinters.

In that occasion, those who left the PD included Vasco Errani,[23] former President of Emilia-Romagna, and deputy minister of the Interior Filippo Bubbico,[24] while Emiliano decided to challenge Renzi in the party's "primaries" instead.

On 3 December 2017 the MDP was a founding member, along with SI and POS, of Free and Equal (LeU), the left-wing joint list for the 2018 general election, which chose the President of the Senate and former anti-Mafia prosecutor Pietro Grasso as its leader and candidate for Prime Minister.

[35] In April 2019 the MDP became a full-fledged party,[36] welcoming new members, notably including David Tozzo from Possible, and being renamed simply as Article One.

[38] During the following government crisis, the national board of the PD officially opened to the possibility of forming a new cabinet in a coalition with the M5S,[39] based on pro-Europeanism, green economy, sustainable development, fight against economic inequality and a new immigration policy.

[42] The LeU groups had previously already announced their possible support to Conte's second government,[43] which was finally unveiled in September with the appointment of Speranza as Minister of Health.