In 2003, while he was living in London he founded the first foreign club association of Freedom and Justice, and two years later he stand for election primaries The Union: after some initial difficulties to achieve the sufficient number of signatures for subscription, is able to submit the application. The primaries are held 16 October 2005 with seven candidates: Scalfarotto placed sixth, collecting 26,912 votes, behind Romano Prodi, who received the investiture of the candidate for Prime Minister of the coalition, Fausto Bertinotti, Clemente Mastella, Antonio Di Pietro and Alfonso Pecoraro Scanio. Among the ideas that inspire his campaign are the main attention to personal merit, public administration and politics, the fight against gerontocracy and support of secularism. Openly gay, is a supporter of the introduction of same sex marriage and the possibility to ask children for adoption by homosexual couples. After his return to work, but moving in the Moscow office, while his supporters founded a political association, "I'm Attending", of which he is president Scalfarotto, to bring forward the ideas that fueled his campaign beyond the primaries of 2005. On 18 June 2007, announces its participation in the primaries of the Democratic Party, in support of the application to the Secretary of Walter Veltroni. Together with others, including Marco Simoni, a university professor, former director of his campaign in 2005, Luca Sofri, and astrophysicist Sandra Savaglio, founded a movement called iMille, with the aim of renewing the ruling class of Italian center-left. Elected to the Constituent National Assembly during the primaries of 14 October 2007, he joined the Commission's Statute of PD, which proposes amendment that provide for the inclusion of a standard anti- homophobia, the creation of SIPA, and the go-ahead to clubs online. It is the first instance of online circle in Italy, which is a candidate for the Chamber of Deputies in college Lombardy 1 in the ranks of the Democratic Party : given the position in the list, turn out to be the first of not elected. He collaborates with the newspaper l'Unità. Back to live in Milan in February 2009, and April is the PD candidate at the 2009 European election on 6–7 June in the North West constituency. Is not elected, but collects more than 22,000 preference. From 7 November 2009 he is the Vice President of the Assembly of the Democratic Party, along with Marina Sereni. They include the extension of marriage to same-sex couples, a stronger fight against homophobia, the establishment of paternity leave and the opportunity to request the correction of ' attribution of sex even without surgery. The 25 September 2012 announces to support Matteo Renzi in the primaries of the Democratic Party. In 2013 he was elected at the Chamber of Deputies after the winning in the 2013 general election.
