Even with rebel armies closing in, Syrian President Bashar al-Assad is showing no hint of a willingness to cede power, raising the prospect of a long, bloody and potentially calamitous final chapter to the country’s civil war, U.S. officials and Middle East experts say.

As his troops battle rebels in Aleppo and other key cities, Assad has rejected new entreaties to accept exile for himself and his family and has repeatedly expressed confidence that loyalist forces will prevail, the officials and analysts said.

His public and private comments suggest that Assad is preparing to follow the example of Libyan leader Moammar Gaddafi, staking his life on his regime’s survival. A growing consensus in Washington and in Middle East capitals now holds that Assad — a man once viewed as a moderate capable of reform — will be forced from power only by death or capture.

“There will not be any negotiations,” said Jeffrey White, a former senior Middle East analyst for the Pentagon’s Defense Intelligence Agency. “He will go down fighting, and he will probably do it in Damascus.”

Senior U.S. analysts who have studied Assad’s recent public appearances described him as increasingly divorced from reality. While they said Assad is neither stupid nor cowardly, he appears to have bought into his own rhetoric, perceiving himself to be the savior of his ethnic clan, the Alawites, as well as the embodiment of the Syrian state. He also appears unfazed by his pariah status, they say.

“Assad is a self-righteous, conspiracy-minded dictator who’s given no indication so far he’s prepared to go quietly into the night,” said a U.S. official with access to intelligence from inside Syria who spoke on the condition of anonymity because of the sensitivity of the assessment. “As with many strongmen before him, Assad’s hubris is leading him into some bad decision making.”

While it is impossible to predict with certainty what Assad will do if faced with imminent defeat, his moves so far suggest that he intends to dig in even deeper.

“He’s backed himself into an increasingly narrow corner,” the official said.

Diplomatic avenues close

The hardening of Assad’s resolve in recent weeks has all but extinguished hopes for a political deal that would hasten his departure and lessen the risk of heavy, block-by-block fighting in Syria’s largest cities. As recently as early July, Secretary of State Hillary Rodham Clinton said it was not too late for Assad to accept such a deal, and White House officials spoke hopefully of an arrangement similar to the one that persuaded Yemen’s longtime president, Ali Abdullah Saleh, to step aside.

Last week, leaders of the 22-nation Arab League put forward a new plan calling for Assad to transfer power to a transitional government in exchange for exile. Qatar’s prime minister, Hamad Bin Jasim al-Thani, urged Assad to make a “courageous” decision to step aside for the sake of his country.

The proposal, which followed a series of private offers by several Arab countries to broker exit deals, was dismissed in Damascus.

The rejection came as Syrian troops shelled Damascus neighborhoods to drive out pockets of rebel troops after a week-long siege. Assad has waged an increasingly destructive campaign against rebel strongholds in the capital and Aleppo, the country’s largest city. The military is using tanks, artillery, helicopters and even fighter jets, reducing neighborhoods to ruins and inflicting untold civilian casualties.

Military analysts and some U.S. officials said the ferocity of the government’s assault makes it clear that Assad believes a fight to the finish is his only option.

Any concession now would run counter to the Assad family’s ruling ethos, said Joshua Landis, a Syria expert and director of the Center for Middle East Studies at the University of Oklahoma.

“It would show weakness, and the nature of his regime is that you never show weakness,” Landis said.

The dictator’s choice to use heavy artillery and helicopter gunships in civilian neighborhoods echoes similar decisions by Assad’s father, who authorized the killing of tens of thousands of Sunni Muslims in putting down a revolt in 1982. Landis said the massive display of state power is the Assad family’s default option, reflecting a calculation that even a fight to the death is preferable to the uncertainty of bargaining for some kind of amnesty.

“It strikes me as foolish, this idea that he’s going to make a deal and leave,” Landis said.

Landis suggested that even if the capital falls to rebels, Assad could be tempted to retreat to an Alawite stronghold within Syria and attempt to hold out as a Lebanon-style militia commander.

Assad’s Western habits and seemingly moderate views had initially inspired optimism among Western acquaintances and Syria watchers about his leadership of the strategically vital country of 20 million. Assad’s pledges to implement political and economic reform once won him prominent admirers in the United States, including Sen. John F. Kerry (D-Mass.), chairman of the Senate Foreign Relations Committee.

Assad, a British-trained ophthalmologist who is married to a British citizen, was an unexpected choice to succeed his notoriously brutal father, Hafez al-Assad, who died in 2000. The younger Assad, 34 at the time, jokingly referred to himself as the “accidental president” of Syria, according one of his biographers, David Lesch, a Middle East historian.

“He was self-deprecating, humble and very much a family man,” Lesch, who writes about Assad’s transformation in a new book, “Syria: The Fall of the House of Assad,” due for release in August, said in an interview. “Gradually he became a bit more imperious in his demeanor. But unlike Saddam Hussein or Gaddafi, you never got the sense that he was eccentric.”

Assad’s shift

Lesch said he met with Assad numerous times over several years after he became president, and saw his personality begin to reflect the insular and paranoid world around him.

In the early years, Lesch said, the young president would joke about the tactics of Syria’s feared Mukhabarat intelligence service. But over time, Lesch said, Assad began to parrot the views of security officials who saw conspiracies and plots everywhere.

“An alternative reality was being constructed around him, and ultimately it sucked him in,” Lesch said. As a result, he added, Assad misread the message of the Arab Spring movement and perceived the Syrian uprising as an incitement by foreign conspirators, with only Assad standing as the guarantor of the country’s salvation.

“In his mind he is fighting against the imperialists and their pernicious allies for the people of Syria,” Lesch said. “He believes that’s his legacy. Perhaps that is the way he will want to go down.”

Against such a hardened and insular perspective, there may be little that outsiders can do, analysts say. The United States severed most trade ties with Syria years ago and has historically had little leverage there.

In most cases, Assad has turned to Arab allies and Russia as interlocutors with the West.

Russia has refused to demand Assad’s ouster. Even as the Aleppo assault swelled over the weekend, Russian Foreign Minister Sergei Lavrov defended the Syrian government.