Romano Prodi, a former visiting professor at Harvard, defeated billionaire Prime Minister Silvio Berlusconi by a close margin in this week’s Italian parliamentary elections.

Prodi, who taught Economics 2364, a course on Italian economic development, in 1974 under the Lauro de Bosis lectureship, captured the election as his center-left party took control of Italy’s two parliamentary houses—the Chamber of Deputies and the Senate.

The elections were held Sunday to Monday, with final returns coming in yesterday.

Though the Interior Ministry has approved vote totals, Italy’s highest court must still confirm the results, and Berlusconi has already called for a recount of the Chamber of Deputies votes.

“Nobody now can say they have won,” Berlusconi said.

Prodi declared victory when his party won the Chamber of Deputies, before the Senate results had officially come in.

Under Italy’s new electoral system, which was instated last year, Prodi’s coalition, the Union, will hold at least 340 of the 630 seats in the Chamber of Deputies even though the party won by a 49.8 to 49.7 percent margin.

In the Senate, Prodi’s party obtained 158 seats versus 156 for Berlusconi’s coalition. The two-seat advantage emerged when overseas voters gave four of their six seats to the Union.

Alberto F. Alesina, who is chair of Harvard’s economics department and Ropes professor of political economy, said Italy’s new electoral system makes it more difficult for a party that wins by a small majority to govern because the system is less “winner-take-all” and more “proportional.”

Alesina said that, although the election results are very tight, it is unlikely that Prodi and Berlusconi will form a coalition.

“Unfortunately, this country is very split,” Alesina said. “But there has been so much animosity between the two camps that it’s going to be very difficult to build coalitions that go across the two camps.”

Alesina said Prodi will also face problems from within his own coalition. The Union includes extreme leftist parties that may veto some of his plans, including important reforms to make Italy’s economy less regulated, according to Alesina.

Alesina described Prodi as being “in between a rock and a hard place,” either “doing nothing or being stopped by the extreme left.” Because of this, Alesina said that he predicts Italy will face “another period of instability” and an “early election in a couple of years.”

Prodi, who was also named prime minister in 1996, faced similar problems when his government fell in 1998 after the Communist Refoundation Party withdrew its support for the Union.

As prime minister, Prodi, who has also served as president of the European Commission, said that he would focus on the European Union.

Saltonstall Professor of History Charles S. Maier ’60 said that Italy “deserves someone who will make it seem like Italy is a member of the European Union.” Maier said that Berlusconi is more “provincial.”

—Material from the Associated Press was used in this article. —Staff writer Claire M. Guehenno can be reached at guehenno@fas.harvard.edu.