Deputy Prime Minister Ahmad Chalabi listened calmly to the contractor's carefully enunciated syllables, the kind a teacher might use with an ignorant student. Then, the MIT-educated mathematician shot back with an eloquent stream of jargon-laced comments that made the engineer's eyes widen.

"So, can we see the turbines now?" Chalabi finished with a grin.

"Absolutely," the humbled Texan replied.

The contractor was only the latest American to learn lesson No. 1 in dealing with Chalabi: Never underestimate him. A year after observers pronounced him finished - spurned by one-time American sponsors and with no apparent political base in Iraq - Chalabi has emerged more powerful than ever.

From his deputy premier's seat in the elected Iraqi government, Chalabi, 60, oversees Iraq's vast oil resources as chairman of the energy council. He presides over a board that regulates multimillion-dollar rebuilding contracts. He commands the controversial purge of former Baath Party members from government posts and the Iraqi Special Tribunal prosecuting Saddam Hussein. Until an oil minister was named, Chalabi held that job, too.

One of his top aides, Entifadh Qanbar, is headed for a plum job at the Iraqi Embassy in Washington. Chalabi's Harvard-educated nephew is the finance minister; rebel Shiite Muslim cleric Muqtada al Sadr is an ally. On a visit to a hospital in southern Iraq, the secular Chalabi was introduced as "the pride of the Shiites," suggesting that at least some members of the majority sect now claim him as their own.

"Chalabi is a clever politician who knows how to get ahead," said Sheik Khalaf al Alayan of the Iraqi National Dialogue Committee, an umbrella group for Sunni factions. "In any place related to money, you can be sure to find Chalabi's people in control."

A comeback of Chalabi's magnitude is hard work, and he started from rock bottom. He'd become an easy scapegoat for the now-unpopular invasion of Iraq after peddling false or exaggerated intelligence to the Bush administration to fulfill his lifelong dream of Saddam's ouster. His pagoda-style villa in Baghdad was ransacked during a probe into allegations of counterfeiting and kidnapping, and American officials accused him of passing secrets to Iran. The Jordanian government asked for his extradition on a 1992 embezzlement conviction.

Abruptly spurned by his hawkish friends in Washington and faced with little street support in Baghdad, Chalabi's star dimmed. Then came a total makeover. He turned critical of the Americans, who a year earlier had airlifted him into Iraq, and relied on Iraqi power brokers to protect his shaky Baghdad empire.

He helped build the United Iraqi Alliance, the Shiite coalition that swept the January elections and installed him as one of three deputy premiers to Prime Minister Ibrahim al Jaafari. An Iraqi court threw out the charges that led to the raid of Chalabi's home, and the judge who signed the search warrant was demoted and fired.

Chalabi has cemented his longstanding relationship with Iraq's Kurdish minority in the north and has reached out to Iraq's disaffected Sunni Arabs, who accuse him of overzealous persecution of the mostly Sunni members of Saddam's former Baath Party. Still, even militant Sunni clerics such as Hareth al Dhari of the Muslim Scholars Association receive their nemesis, albeit with a challenge summed up as: You brought the Americans, you get them out.

"After America saw the real Chalabi and abandoned him, he turned to the tribal and religious movements," said Hazem Ali, a political analyst at Baghdad University. "It's campaign season for the elections. He's going to do whatever he can to get votes."

Even the U.S. government has warmed to Chalabi again. American officials never pursued the allegation that his associates passed intelligence to Iran, and both U.S. Vice President Dick Cheney and Secretary of State Condoleezza Rice called Chalabi to congratulate him on his election win. He accepted the U.S. military's offer to train his phalanx of bodyguards. And he attended the American Embassy's Fourth of July celebration, where diplomats and U.S. military commanders greeted him like an old friend.

Even his most bitter rivals exhibit a grudging admiration for Chalabi's phoenix-like ability to reinvent himself, though some complain he deals without principle to advance himself.

"This is his problem," said Sheik Homam Hamoodi, a senior Shiite politician who leads the drafting committee for the Iraqi constitution. "This comes from his background as a banker. ... He sells and buys without a specific strategy."

Chalabi rejects claims that he lacks popular support. While he said it's "too early" to talk about his plans for the December elections, he's obviously hard at work on his latest makeover.

This time, he's fashioning himself as an Iraqi patriot able to reach across Iraq's sectarian lines. He's even become something of a populist, as one of the very few leaders to live outside the U.S.-guarded Green Zone compound or to risk the perilous roads leading out of the capital. Last week, he made a dangerous foray south along a route where gunmen had previously ambushed his convoy.

Chalabi wanted a firsthand look at the aftermath of the inferno in Musayyib, a tiny, mostly Shiite village where a suicide bombing killed nearly 100 people this month. He pored over maps with local Iraqi authorities, recreating the bomber's path. He comforted survivors in a rank hospital. He paused to gaze at the shimmering Euphrates River.

He glad-handed two American soldiers stationed in the area, thanking them for helping to get rid of Saddam. Then he was gone.

"Um, who did I just meet?" asked a bewildered Lt. Col. John Rhodes of the 155th Separate Armored Brigade.

"Remember the guy the CIA cut off, the one pumping the bad intelligence that got us over here in the first place? That was him," the other soldier replied.

"Oh, yeah. That guy," Rhodes said with a shrug.

Many Iraqi leaders found out about the trip only when the state-run television station showed Chalabi touring the bombing site. Grandstanding, his Shiite allies privately griped. Days later, however, Jaafari followed suit by presiding over a luncheon at the prime minister's office for the parents of children killed in another suicide bombing.

Chalabi denied that the Musayyib visit was early campaigning.

"I do the right thing for the people who have suffered," Chalabi said, snacking on Iraqi apples as his convoy of 20 white Land Cruisers sped back to Baghdad. "If there are other interpretations, that's up to them."

In the shifting landscape of Iraqi politics, holding onto power is a full-time job that leaves Chalabi unable to pursue his many intellectual interests. His Lebanese wife and their four children live mostly outside of Iraq, and his taxing schedule seldom permits travel abroad. In the past week, however, Chalabi entertained a houseguest: the Lebanese-born scholar Fouad Ajami, a pariah among many Arab intellectuals for his cozy relationship with Israel and the United States.

Ajami, director of Middle Eastern Studies at Johns Hopkins University's School of Advanced International Studies, had accompanied Chalabi on the solemn trip to Musayyib. Over a traditional Iraqi meal of cinnamon-spiced rice and okra stew later that evening, the like-minded men skewered their mutual critics, lambasting an array of self-proclaimed Iraq experts, the Arab intelligentsia, famous journalists and Washington lawmakers. After dinner, Ajami and Chalabi's aides, exhausted by the grueling day, sank into plush chairs.

Chalabi disappeared for a moment to swap his dusty suit from the bombing tour for a crisp navy blazer. He said good night to his guests and set off for a Cabinet meeting.

"We'll rest now," said Qanbar, one of Chalabi's closest aides. "But he'll keep going until midnight."

Before Ajami left town, Chalabi did manage to carve out a leisurely summer day at the picturesque, poolside Baghdad estate built by his father in 1934. They lounged in a room where the television was tuned to coverage of Condoleezza Rice's visit to Beirut, and a boxed set of "The Sopranos" sat on a shelf. The men discussed authors and debated Arab contributions to science as Moroccan folk music, Palestinian rap and Lebanese pop boomed from a stereo. Chalabi's nephew, the finance minister, joined them for lunch.

Sporting chinos and a Nike T-shirt, Chalabi led a visitor through his family's majestic, century-old palm groves and a greenhouse built with reeds from Iraq's southern marsh country. The raw ambition and ruthlessness he often exhibits in the political arena melted away as he strolled around his boyhood retreat.

Chalabi's roots are in the landed Iraqi aristocracy that was close to the former monarchy. He was born in the Baghdad neighborhood of Adhemiyah and still keeps a family home there, though the area has become a haven for Sunni insurgents. He left at age 14 and as an adult fought his way into the leadership of the Iraqi opposition in London. The bitterness of his four decades of exile became apparent as he lovingly described the taste of Iraqi dates and the elegant architecture of the poolside cabana his father added to the house as a gift to his young son in the 1950s.

Chalabi mentioned he was reading "The Orientalist," the acclaimed biography of a Russian Jew who masqueraded as a Muslim prince early last century. Chalabi seemed fascinated by the fabulist at the heart of the story. As one literary critic wrote of the character: "Inventing and reinventing himself, he left a confused and perplexing trail."