A member of the right-wing faction of the Christian Democracy (DC) party, Forlani was one of the most prominent Italian politicians from the 1970s to early 1990s.

Forlani's permiership, which lasted less than a year, was strongly marked by the 1980 Irpinia earthquake and the P2 lodge scandal, the latter causing his resignation in June 1981.

In 1981, together with Bettino Craxi and Giulio Andreotti, he promoted the Pentapartito, the political coalition between the three major Italian parties that ruled Italy between 1981 and 1991.

[6][7] Forlani assumed the leadership of the party in a moment of social instability provoked by the mobilizations in the universities and factories, for which he drafted the Preambolo, to ask the Italian Socialist Party to be part of a center-left government in order to break all relations with the communists in the municipal administrations and the trade unions.

At the end, the DC proposed Giovanni Leone, former prime minister and long-time president of the Chamber of Deputies, who was elected with the support of the neo-fascist Social Movement.

[13][6] The reasons of this important nomination were firstly the necessity to recover a climate of unity in the party after the congressional divisions and secondly the opportunity, in a world still marked by the Cold War, to allocate foreign policy to a clearly anti-communist personality, as Forlani was, able to calm the European and U.S.

Due to his fundamental role in Piccoli's election, Forlani was appointed Prime Minister of Italy in October, leading a centre to centre-left coalition with PSI, PSDI and PRI.

Of the billions of lire that were predestined for aid to the victims and rebuilding, the largest part disappeared from the earthquake reconstruction funds in the 1980s.

In its latter period, during which the lodge was headed by Licio Gelli, P2 was implicated in numerous Italian crimes and mysteries, including the collapse of the Vatican-affiliated Banco Ambrosiano, the murders of journalist Mino Pecorelli and banker Roberto Calvi, and corruption cases within the nationwide bribe scandal Tangentopoli.

[28] The lodge had among its members prominent journalists, Members of Parliament, industrialists, and military leaders—including Silvio Berlusconi, who later became Prime Minister of Italy; the Savoy pretender to the Italian throne Victor Emmanuel;[29] and the heads of all three Italian intelligence services (at the time SISDE, SISMI, and CESIS).

With his resignation and the appointment of Republican leader Giovanni Spadolini, the unbroken line since 1945 of Christian Democratic Prime Ministers came to an end.

[6] He managed as secretary the long government crisis that followed the 19 May 1989 resignation of Ciriaco de Mita as prime minister after strong contrasts with Bettino Craxi.

[35] In July, the sixth Andreotti government took office and, after the good results of the DC in the 1989 European Parliament election, promoted the so-called "C.A.F."

[36] Forlani, at the end of 1991, convened the National Programmatic Conference of the DC in Milan in which he warned that the First Republic was collapsing and identified possible, being the reform of the proportional electoral law that included a 'corrective majority' one of his main remedies.

[6][4] That conviction, added to the failed race for the presidency of the country and the bad results in the 1992 Italian general election, put an end to his political career.