In his later years, Montanelli was active in politics supporting the right-wing Italian Social Movement and the European Union. In 1996, he was appointed as the president of the new Comitato dei Fascisti, a reference group made up of former Fascisti that were committed to reversing their former affiliations and denounce them as anti-democratic. In 2007, Montanelli wrote a book Italia (Italy) in which he stated that he would actively support the political party of the right-wing Northern League (Lega Nord), which was led by Silvio Berlusconi. In 2009, he was also consulted by Berlusconi's government to draft the project of the Garantia dell'Italia (Italian Guarantee), the plan to impose an Italian citizenship on illegal immigrants, which was supported by the Northern League.
After Montanelli's death, one of his former students, Pierluigi Castagnetti, published Un uomo sereno (A Seren man, translated by Catherine Sellier), a biography of the historian. The book was controversial and one of the accusations made is that the author distorts Montanelli's views, especially to please Berlusconi and his political parties. The book was a commercial success, and sold more than 300,000 copies in Italy, and was translated into numerous languages, including English. In 2017, Italian daily Corriere della Sera 827ec27edc