MONTREUX, Switzerland — At the core of the extraordinary diplomatic push launched Wednesday to end Syria’s civil war is the fate of one man: Syrian President Bashar Assad.

Assad has steadfastly maintained power during nearly three years of war and hints he may run for re-election this year. But the Obama administration and the U.S.-backed opposition have said Assad must step down in any peace deal.

That strategy may have backfired, contributing to a protracted conflict, a radicalization of the armed opposition and a consolidation of Assad’s support.

While Assad is at the center of the debate about Syria, his future has significance far beyond the country’s borders.

Syria is one of the key pieces of a delicate reordering of the political map of the Middle East. The conflict has become a proxy war in the regional conflict between Sunni Muslims and Shiite Muslims.

The U.S. effort to end decades of estrangement with Shiite Iran, starting with an interim deal to limit its nuclear program, has further angered longtime ally Saudi Arabia, Iran’s Sunni archrival. The monarchy already was upset that Washington has not been more aggressive against Assad, Iran’s longtime ally.

Few expect the peace negotiations, which move to Geneva on Friday for face-to-face meetings between the government and the opposition, to reach a swift resolution.

A NON-NEGOTIABLE ISSUE

Washington appeared to be doubling down on the demand that Assad must go.

The “only thing standing” in the way of a political solution is “the stubborn clinging to power of one man, one family,” Secretary of State John F. Kerry told the conference, adding: “One man and those who have supported him can no longer hold an entire nation and a region hostage.”

Assad, who was not at the conference, showed no sign of backing down.

Syrian officials and their Russian allies have indicated flexibility on a number of issues, including possible cease-fires, prisoner exchanges and bolstered humanitarian access to besieged areas. But Syria says Assad’s future is nonnegotiable.

“Syrians alone have the right to choose their government, their parliament and their constitution,” Syrian Foreign Minister Walid Moallem told diplomats who had come to Montreux from more than 30 nations, most seemingly hostile to Assad. “Everything else is just talk and has no significance.”

Moallem said any deal brokered in Geneva is subject to a national referendum. Assad seems confident he could win an election – though balloting would be of questionable legitimacy amid a civil war.

During the war, the radicalization of the opposition, including the growth of al-Qaida and other militant Islamic elements, has bolstered Assad’s support in some quarters. That is especially the case among Christians and other minorities and among many secular-minded Syrians appalled at the prospect of an Islamist takeover.

FOUR DECADES OF POWER

Assad stands atop a dynastic power structure more than four decades in the making, set in place by former President Hafez Assad, the current leader’s late father.

In the 1980s, the elder Assad oversaw the military crushing of an Islamist uprising viewed by his son as an earlier incarnation of the current revolt. Bashar Assad is also the standard-bearer of Syria’s Alawite minority, many of whose members view the revolt led by the Sunni Muslim majority as a matter of survival.

U.S. officials are keen to avoid direct military involvement in a potential quagmire and a complete collapse of Syria. Diplomats fear the kind of chaos that followed the U.S.-led ouster of Saddam Hussein in neighboring Iraq in 2003.

Syria’s major allies, Russia and Iran, have asserted that they are not tied to propping up Assad’s rule. But many Western diplomats are skeptical. Syria is Russia’s last major strategic bastion in the Middle East. And, for Iran, Assad’s Syria is a central component of its “axis of resistance” partnership with Hezbollah, the Lebanese-based political and military group.

President Obama stated publicly in August 2011 that Assad should step down from office. Expectations in Washington and other global capitals that Assad’s trajectory would mirror the relatively quick exits of Egyptian and Tunisian strongmen caught in “Arab Spring” uprisings were off base. Unlike in Tunisia and Egypt, the Syrian military backed Assad and carried out his crackdown on dissent.

Despite its oft-stated antipathy toward Assad, Washington has also shown a willingness to work with his government when necessary. The deal reached last year to avert U.S. airstrikes was contingent on Assad’s willingness to renounce his chemical weapons stockpiles under international supervision.

Some observers, notably Ryan Crocker, a former U.S. ambassador to a number of Mideast and South Asian countries, have said that Assad is unlikely to fall and it would be wise for Washington to engage his government as an alternative to Islamic radicals. But Kerry’s comments in Montreux indicate that the U.S. remains intent on Assad’s departure.

Kerry regularly cites the “Geneva communique,” a kind of peace road map hammered out in June 2012 during a United Nations-organized summit.

But the document does not explicitly call for Assad’s ouster..

In Syria’s view, it is Washington and its allies who are violating the spirit of Geneva by focusing on one aspect – the removal of Assad – that the accord did not explicitly call for. With Moscow backing Syria’s interpretation of the Geneva communique, the barrier to forcing Assad’s ouster would seem a formidable one.