For 37 years the border between Israel and Syria, still technically at war, has proven as quiet as any of the Arab-Israeli frontiers silenced by peace agreements. On Sunday, it was not, and the tumult on the Golan Heights could augur a new phase of the uprising against President Bashar al-Assad and the web of international relations he is navigating.

Predictably, Israel and Syria blamed each other for the bloodshed — Israeli soldiers killed four people as hundreds stormed the border. But the message was far more important, since the Syrian government, which controls access to the border, allowed crowds to venture to a place it had all but declared off limits until now. For the first time in his 11-year reign, Mr. Assad demonstrated to Israel, the region and world that in an uprising that has posed the greatest threat to his family’s four decades of rule, he could provoke war to stay in power.

Few questioned the sincerity of the Palestinian refugees who flocked to the border; the day that marks Israel’s creation remains a searing date in the Palestinian psyche, and they cited the upheavals of the Arab Spring as inspiration. But as is often the case in modern Arab politics, they may have found themselves in a more cynical conflict that involves power, survival and deterrence and in which, to varying degrees, Iran, Israel, Turkey and the United States have a stake in the survival of a government that is bereft of legitimacy except as a force for a notion of stability.

“It’s a message by the Syrian government for Israel and the international community: If you continue the pressure on us, we will ignite the front with Israel,” said Radwan Ziadeh, a Syrian dissident and visiting scholar at George Washington University.

The message carried profound risks in a combustible region. Israel is perceived as preferring Mr. Assad’s government to an alternative that could empower Islamists, though Israeli officials stringently deny that. Poorly equipped and neglected, Syria remains utterly incapable of waging war, with its military deployed across the country in a ferocious crackdown on the two-month uprising. And even in Syria, some suspected that the Palestinians were being manipulated, though some warned that an even more aggressive Israeli response could quickly change that.

“Oh, Maher, you coward, send your army to the Golan,” protesters chanted just last week at Mr. Assad’s brother, who leads the elite Republican Guard and the Fourth Division, which has taken the lead in military operations against restive cities.

“The idea of war against Israel hasn’t even been part of Syria’s mindset for a long time,” said Louay Hussein, a prominent dissident who met with an adviser to Mr. Assad last week in what the government has called the beginning of a dialogue. “The Syrian government doesn’t have a strategy. Its political performance is based on improvisation.”

Unlike the Lebanese border, still a tense region where Israel and Hezbollah fought a devastating and inconclusive war in 2006, Syria’s border on the Golan Heights has remained remarkably quiet since a truce in 1974 that followed war a year earlier. Seized by Israel in the 1967 war, it remains at the heart of the two countries’ enmity, though Syria has long indicated it holds out little chance to recover it except through negotiations.

To many in the Arab word, the frontier’s longstanding quiet has even become a source of jokes, especially as Syria chose to pressure Israel through proxies beyond its borders, particularly with Hezbollah in Lebanon. In Arabic, Assad means lion, thus the taunt of Mr. Assad’s father, Hafez: “A lion in Lebanon, but a rabbit in the Golan.”

The uprising, though, has already recast regional relations, placing Syria squarely on the defensive. Though government officials claim the upper hand, the military is deployed from the southern steppe to the Mediterranean coast. Seven people were reported killed on Sunday in Talkalakh, near the Lebanese border, the latest target of the military’s attempt to quell dissent. Relations with Turkey have soured, and the United States and Europe have imposed sanctions.

In Lebanon, Syria’s ally Hezbollah is said to be anxious, and its television station, al-Manar, conspicuously omits almost any mention of the uprising in Syria. In a frank interview last week in Damascus, Rami Makhlouf, Syria’s most powerful businessman and a confidant and childhood friend of Mr. Assad, warned the international community against imposing pressure on the Syrian government. Syria’s instability, Mr. Makhlouf said, would mean instability for Israel, too.

“To have stability in Syria is the most important thing for the stability of the neighbors,” he said in the interview. “Which neighbors? Israel.”

The frontier along the Golan Heights, a strategic rocky plateau, is the most sensitive in Syria, and checkpoints proliferate. Even for Syrians, permission is required to enter some parts of it. In an authoritarian state, the government also keeps relentless surveillance over the 10 official Palestinian camps and three unofficial ones.

Mr. Ziadeh, citing informants in Damascus, said at least four buses were seen Saturday leaving two camps where factions most loyal to Syria exert control.

“For 40 years, the Syrians have very effectively prevented infiltration, which shows that the Syrians have their hand on the faucet,” said Yoni Ben-Menachem, an Israeli analyst. “This also demonstrates the unwillingness of both Israel and the U.S. to see the removal of Bashar Assad” — as long as he keeps the border with Israel quiet.

Relatively poor, with a population that pales before countries like Egypt, Syria has long played an assertive role in the region by making itself a linchpin. Though avowedly secular, it has deep ties with Islamist movements like Hamas in the Palestinian territories. The same goes for the Islamic republic in Iran, its closest ally.

The ambiguity of its foreign policy has prompted American officials to hold out hope that Syria could be lured away from its alliance with Iran and its allies. Mr. Assad’s geniality — he is famous for agreeing but not delivering — helped lead Turkey to deepen its relationship with a country it saw as a hub for its vision of regional integration.

Both the United States and Turkey have denounced the crackdown, but stopped short of calling for Mr. Assad’s departure, a step with far-reaching implications for the leadership’s survival. That was in part motivated by fear of what might follow Mr. Assad’s fall, analysts say, an anxiety that the government has relentlessly sought to cultivate since the uprising began. The violence on Sunday, analysts say, might have been stage-managed foreshadowing.

“It’s going to be messy,” an Obama administration official said of the government’s determination to survive. “He’s going to hang on for dear life.”