The project of a Democratic Party was often mentioned by Prodi as the natural evolution of The Olive Tree and was bluntly envisioned by Michele Salvati, a former centrist deputy of the DS, in an appeal in Il Foglio newspaper in April 2013.

Also leading external figures such as Giuliano Amato, Marcello De Cecco, Gad Lerner, Carlo Petrini and Tullia Zevi were included.

[24] On 18 June, the committee decided the rules for the open election of the 2,400 members of the party's constituent assembly; each voter could choose between a number of lists, each of them associated with a candidate for secretary.

A total of ten candidates officially registered their candidacy: Walter Veltroni, Rosy Bindi, Enrico Letta, Furio Colombo, Marco Pannella, Antonio Di Pietro, Mario Adinolfi, Pier Giorgio Gawronski, Jacopo Schettini, Lucio Cangini and Amerigo Rutigliano.

Of these, Pannella and Di Pietro were rejected because of their involvement in external parties (the Radicals and Italy of Values respectively) whereas Cangini and Rutigliano did not manage to present the necessary 2,000 valid signatures for the 9 pm deadline and Colombo's candidacy was instead made into hiatus to give him 48 additional hours to integrate the required documentation.

In the words of Ermete Realacci, green represents the ecologist and social-liberal cultures, white the Catholic solidarity and red the socialist and social democratic traditions.

The early months after the election were a difficult time for the PD and Veltroni, whose leadership was weakened by the growing influence of internal factions because of the popularity of Berlusconi and the dramatic rise of IdV in opinion polls.

Prior to the election, the PD considered offering hospitality to the Socialist Party (PS) and the Greens in its lists, and proposed a similar pact to Democratic Left (SD).

The national convention and a subsequent open primary were called for October,[38][39] with Franceschini, Pier Luigi Bersani and Ignazio Marino were running for the leadership,[40][41] while a fourth candidate, Rutigliano, was excluded because of lack of signatures.

In September 2011, Bersani was invited by Antonio Di Pietro's IdV to take part to its annual late summer convention in Vasto, Abruzzo.

Bersani, who had been accused by Di Pietro of avoiding him to court the centre-right UdC,[50] proposed the formation of a New Olive Tree coalition comprising the PD, IdV and SEL.

[52][53] The pact was broken after the resignation of Silvio Berlusconi as Prime Minister in November 2011, as the PD gave external support to Mario Monti's technocratic government, along with the PdL and the UdC.

[56][57] In the primary, the strongest challenge to Bersani was posed by a fellow Democrat, the 37-year-old mayor of Florence Matteo Renzi, a liberal moderniser, who had officially launched his leadership bid on 13 September 2012 in Verona, Veneto.

On 28 April, Enrico Letta, the party's deputy secretary and former Christian Democrat, was sworn in as Prime Minister of Italy at the head of a government based around a grand coalition including the PdL, Civic Choice (SC) and the UdC.

Epifani, secretary-general of the Italian General Confederation of Labour (CGIL), Italy's largest trade union, from 2002 to 2010, was the first former Socialist to lead the party.

They comprised splinters from SEL (most of whom led by Gennaro Migliore, see Freedom and Rights), SC (notably including Stefania Giannini, Pietro Ichino and Andrea Romano) and the M5S.

[104] Subsequently, a substantial group of leftists (24 deputies, 14 senators and 3 MEPs), led by Enrico Rossi (Democratic Socialists) and Roberto Speranza (Reformist Area), backed by Massimo D'Alema, Pier Luigi Bersani and Guglielmo Epifani, left the PD and formed Article 1 – Democratic and Progressive Movement (MDP), along with splinters from the Italian Left (SI) led by Arturo Scotto.

In December 2017, the MDP, SI and Possible would launch Free and Equal (LeU) under the leadership of the President of the Senate Pietro Grasso[110][111] (another PD splinter).

[130][131] Three major candidates, Martina, Nicola Zingaretti and Roberto Giachetti, plus a handful of minor ones, formally filed papers to run for secretary.

[146] After Conte's resignation, the national board of the PD officially opened to the possibility of forming a new cabinet in a coalition with the M5S,[147] based on pro-Europeanism, green economy, sustainable development, fight against economic inequality and a new immigration policy.

[154] On 18 September, Renzi, who had been one of the earliest supporters of a M5S–PD pact in August,[155] left the PD and established a new centrist party named Italia Viva (IV).

[176] In the midst of the formation of Draghi's government, Zingaretti was heavily criticised by the party's minority for his management of the crisis and strenuous support to Conte.

A few days before the closing of coalitions and lists, Calenda announced that he was walking away from the pact he has signed with Letta because of the subsequent alliances that the PD had formed, notably including that with the AVS.

[204][205][206] The IDP list offered a broad range of candidates, including some high-profile independents: left-wingers like Susanna Camusso and Elly Schlein,[207][208] the liberal economist Carlo Cottarelli, Christian-democrat and long-time MP Pier Ferdinando Casini,[209][210] scientist Andrea Crisanti,[211][212] etc.

[231] Other leading candidates include Giorgio Gori, Matteo Ricci and Antonio Decaro (outgoing mayors of Bergamo, Pesaro and Bari, respectively), as well as former party leader Zingaretti and Marco Tarquinio, a social-conservative and pacifist journalist.

In 2009, Alfred Pfaller observed that the PD "has adopted a pronounced centrist-pragmatic position, trying to appeal to a broad spectrum of middle-class and working-class voters, but shying away from a determined pursuit of redistributive goals".

[240][241] Inspired by Renzi, re-elected secretary in April, and Marco Minniti, interior minister since December 2016, the party promoted stricter policies regarding immigration and public security.

[242] These policies resulted in broad criticism from the left-wing Democrats and Progressives (partners in government) as well as left-leaning intellectuals like Roberto Saviano and Gad Lerner.

[262][263][264] Some pundits hinted that the Bersani-Franceschini pact was envisioned in order both to marginalise Veltroni and to reduce the influence of Massimo D'Alema, the party bigwig behind Bersani, whose 2009 bid was supported primarily by Dalemiani.

[275] As the party performed below expectations, more Democrats started to look at Renzi, who had been defeated by Bersani in the 2012 primary election to select the centre-left's candidate for prime minister.