ROME » He sometimes wears a leather bomber jacket, embracing the iconography of the rebel. He has rocketed through Italian politics by taking on the establishment, especially in his own left-leaning party. He is media savvy, evoking comparisons to Tony Blair, and he has tapped into a national yearning for change by cultivating a persona as a political wrecking ball with an everyman appeal.

And now, in swift and stunning fashion, Matteo Renzi, only 39, a former Boy Scout and "Wheel of Fortune" winner, has arrived as the central figure in Italian politics — and a new force in Europe — with an agenda that seems as much psychological as political: to shake Italy out of its malaise, push through major changes and shatter the entrenched old guard that dominates politics but has failed to reverse Italy’s painful decline.

It is the tallest of orders, made more difficult by the circumstances of Renzi’s ascent. Rather than winning a national election, his long-stated goal, Renzi this week engineered the removal of Enrico Letta, the sitting prime minister and a member of his own Democratic Party. Critics said the move smacked of the old-style insider politics Renzi claims to oppose, even as admirers called it an unpleasant necessity and a bold gamble.

"The odds are against Renzi," said Sergio Fabbrini, director of the Luiss School of Government in Rome. "But against these odds is a young politician with a significant personality. I just don’t know if that personality is enough."

Within days, Renzi, who has been a rising national star since he became mayor of Florence in 2009, is likely to be installed as Italy’s next and youngest prime minister. On Friday, Letta handed in his resignation to Italy’s president, Giorgio Napolitano, and by next week Parliament could be asked to complete the transition in a confidence vote that Renzi is expected to win.

Renzi has drawn comparisons to Blair, the former British prime minister, not only because of his style and generational appeal but also because he has confronted the leftist ideology of his party and embraced a more business-friendly approach, promising to cut corporate taxes and overhaul labor laws.

Renzi’s rise also speaks to Italy’s predicament in a Europe still convulsing from the aftermath of the economic crisis. Southern tier countries like Greece, Portugal and Spain have had to push through painful economic changes or risk losing the financial lifeline provided by the troika of international lenders.

Italy has avoided an outside bailout, and as a result it has been spared the extreme shock therapy endured by its southern neighbors. But this has allowed the political establishment to remain largely intact, without making major changes, even as the economy remains stagnant.

This state of affairs has fueled popular support for anti-establishment figures like comedian Beppe Grillo, founder of the Five Star Movement, and it created an opening for Renzi to take control of the Democratic Party by arguing that the old guard was a spent force.

"Renzi is proof that the Democratic Party has undergone a genetic mutation," said Angelo D’Orsi, a professor of political theory at the University of Turin, noting that the party’s historic links to Italy’s old Communist Party are now severed.

Renzi first captured national attention four years ago when he spoke openly about the need to dump Italy’s political class by using a colloquial verb, rottamare, which roughly translates as junking an old car or appliance in a scrapyard. The expression took off, fueled by the Internet and social media, and Renzi has used the hashtag rottamare on Twitter.

In a country where much of the younger generation feels alienated and struggles to find work, Renzi’s youth and open-collared, sleeves-rolled-up style have resonated. Born in Florence to parents who now own an advertising agency, Renzi was a class officer in high school, a longtime Boy Scout and an altar boy at his Roman Catholic parish. As a teenager, he even won thousands of dollars on Italy’s version of the television game show "Wheel of Fortune."

"He was always organizing something, always arranging things," said Don Giovanni Sassolini, the priest who celebrated Renzi’s communion and confirmation, recalling that on the soccer pitch, the young Matteo "always wanted to be the striker."

Renzi married (he and his wife, Agnese, now a high school teacher in Florence, have three children), and then he decided, at age 29, to run for the presidency of Florence’s provincial council, a relatively minor body. By 2009, Renzi bucked the local Democratic Party establishment and challenged the party’s entrenched incumbent in the mayoral race. He won.

His theme was established: Change is what Florence needs, what Italy needs, and he is the agent of change. He later met President Barack Obama during a visit to Washington and has proudly shown a photograph of the two men to visitors.

But Renzi’s relentless politicking and his telegenic sheen have brought criticism that he is more style than substance. In Florence, he claimed full credit for the creation of a pedestrian zone in the city’s main tourist area, surrounding the Duomo, even though the project was set in motion before he took office. More recently, some Florentines have grumbled that his focus has been elsewhere as he has positioned himself for national office.

"There is no substance to back it up," said D’Orsi, speaking of Renzi’s public campaigning.

Alberto Ferrarese, a journalist and co-author of a political biography of Renzi, said Florence had improved under his mayoralty, especially the city center, but his impact was less significant on major infrastructure issues. Ferrarese said Renzi had changed the political culture, bicycling around the ancient city, meeting with citizens on the street and cultivating an Ordinary Joe persona.

Antonio Salvi, a Florentine barber, said Renzi comes by every week or 10 days to maintain his short hairstyle, and sometimes steps into the suntan bed as he talks politics with his aides.

"He sits for two or three minutes in the sun bed," Salvi said. "They talk, but I don’t listen. It’s their private time."

Renzi made his big national move in 2012, when he sought the leadership of the Democratic Party in a nationwide primary that preceded parliamentary races. Pier Luigi Bersani, the embodiment of the old guard, defeated him, but Bersani then performed badly in inconclusive parliamentary elections last February.

Napolitano, the president, had to form a wobbly coalition of left and right parties, naming Letta as prime minister. Nine months later, Renzi again ran in a primary to become leader of the Democratic Party and won in a landslide.

Now, Renzi faces an array of challenges. Italy’s electoral politics have been frozen since the country’s highest court declared the voting law to be largely unconstitutional. Analysts say that one reason Renzi decided to push out Letta as prime minister was that his administration was moving too slowly to pass a new election law, creating the possibility that the government could be frozen in place for an indefinite period.

Ever the maverick, Renzi now must also prove he can build a team and demonstrate the administrative skill to bring to heel Italy’s notorious bureaucracy. He also inherits the same unwieldy coalition that often made it difficult for Letta to achieve big economic and political changes. Analysts say he is taking a huge risk, one that could doom his political career — or define it.

In his speech before party leaders Thursday, in which he called for Letta’s ouster, Renzi acknowledged the risk with a typical rhetorical flourish, comparing it to the risks taken by mothers, small business owners and others confronted daily with the obstacles presented by government in Italian life.

"This road is more difficult, rather than waiting for a slow attrition," he said "because putting myself on the line now has an element of personal risk."

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