One of their leaders, Walter Veltroni, who ran in ticket with Prodi in a long electoral campaign, was Deputy Prime Minister. On 9 October 1998, the Prodi I Cabinet fell when PRC left the alliance. Since 21 October 1998 The Olive Tree was the core of the governments led by Massimo D'Alema and by Giuliano Amato. When D'Alema became Prime Minister, it was the first time ever in both Italy and Western Europe that an heir of the communist tradition came to lead a government. On 13 May 2001, led by Francesco Rutelli, who ran in ticket with Piero Fassino, the coalition lost the general elections against Silvio Berlusconi and his House of Freedoms centre-right coalition. The Union was the direct heir of The Olive Tree coalition. However, The Union was an heterogenous alliance that also included parties of the radical left, which were not part of The Olive Tree. Romano Prodi won the April 2006 general election by a very narrow margin due to Calderoli new electoral law, although Silvio Berlusconi first refused to acknowledge defeat. Prodi's coalition proved to be extremely frail, as the two-vote margin in the Senate allowed almost any party in the coalition to veto legislation and political views inside the coalition spanned from far-left Communist parties to Christian Democrats. The centre-left majority coalition, on 7 May 2006, officially endorsed Giorgio Napolitano as its candidate in the presidential election that began on 8 May. The Vatican endorsed him as President through its official newspaper, "L'Osservatore Romano", just after The Union named him as its candidate, as did Marco Follini, former secretary of the Union of Christian and Centre Democrats, a member party of the House of Freedoms. Napolitano was elected on 10 May, in the fourth round of voting — the first of those requiring only an absolute majority, unlike the first three which required two-thirds of the votes — with 543 votes (out of a possible 1009). At the age of 80, he became the first former Communist to become President of Italy  Less than a year after he had won the elections, on 21 February 2007, Prodi tendered his resignation to President Napolitano after the government was defeated in the Senate by 2 ballots in a vote on foreign policy. On 24 February, President Napolitano invited him to return to office and face a vote of confidence. Major causes of friction inside the coalition were, the 2006 pardon Act (criticised by the right and by the Italy of Values party), a draft bill to establish civil unions (vetoed by Christian Democrats), Italy's continued involvement in Afghanistan (strongly opposed by left-wing parties), and finally the much publicised house-arrest of Clemente Mastella's wife (then a prominent politician at the regional level) over a corruption scandal.