GAZIANTEP, Turkey—The thumbs-up a top rebel commander flashes at me as he returns to this Turkish border town from the front-lines of northern Syria’s battlefields speaks volumes.

There has been little for Syrian insurgents to cheer about in recent months. Even a few weeks ago this man was downcast and appeared adrift and unable to imagine an end to a war that has claimed the lives of 6,000 of his men.

But a new Islamist alliance of brigades backed by al Qaeda affiliate Jabhat al Nusra is moving ahead aggressively against the forces of President Bashar al-Assad and the emboldened insurgents, fresh from two significant battlefield gains, say that the four-year-long civil war is entering a new and critical phase—one that didn’t appear likely, or even possible, as recently as February.

And as the gains pile up, talk is intensifying within Jabhat al Nusra, and especially among the group’s Syrian commanders and fighters, of breaking with al Qaeda—a move they hope might entice the West to support this offensive and impose a no-fly zone across northern Syria.

The capture of the cities of Idlib and, last weekend, Jisr al-Shughour had major symbolic significance. This is where the armed rebellion against Assad began in June 2011, after Assad’s security forces fired on a funeral demonstration. And it has boosted the fighters’ morale. The newly confident Sunni rebel militias are focusing now on objectives to the south, seeking to block Syrian government supply lines from the regime’s coastal stronghold of Latakia. That would force the Assad regime to supply it’s remaining forces in the province of Idlib and the city of Aleppo only from Damascus.

Such is the rebels’ soaring confidence that they talk of taking the war out of northwest Syria and positioning themselves either to put pressure on Latakia or strike south towards Hama, affording them the opportunity to threaten the Syrian capital and coordinate more with rebel militias in the southern and eastern suburbs of Damascus.

From the despair and anger of December and January, when Assad’s forces appeared a skirmish away from encircling rebel-held districts in Aleppo and severing insurgent supply lines to Turkey, the transformation is remarkable. Back then, plagued by infighting and demoralized by the US-led coalition’s focus on the jihadists of the self-styled Islamic State, Syrian rebels were directionless and pessimistic about their chances of toppling Assad. I met many fighters who were throwing in the towel and deciding they had had enough after four years of struggle.

Fighters blamed the West, the Sunni monarchies of the Gulf Arab states and Turkey for their plight, seeing their refusal to supply more advanced weaponry as a betrayal and evidence of duplicity by Washington. They argued the Americans preferred for Assad to remain in power, and accused President Barack Obama of buying into Assad’s argument that his ouster would result in the caliphate of the Islamic State enlarging to include the whole of Syria—that either he is the ruler of Syria or Abu Bakr al Baghdadi will be.

Western-backed militias saw their arms supplies and cash from Washington reduced significantly or in some cases cut altogether. U.S. officials argued this was performance-related or punishment for their fighting alongside hardcore Islamist brigades and al Nusra. Rebel commanders suspected the cuts were designed to force rebels to leave their brigades and enlist in the U.S.-planned train-and-equip program for the raising of a Syrian rebel proxy force to take on the Islamic State, still widely known as ISIS.

Anger at the West and the Gulf states hasn’t subsided. Rather, it has turned to disdain.

Inspiring this new-found coordination among the rebel militias that have made such gains is the realization that they can’t rely on anyone but themselves. Their attitude, emphasized to me by several rebel commanders and fighters I have spoken with over the past week, is that the World has let them down and so it is up to them now.

Western analysts have given credit for the capture of Idlib and Jisr al-Shughour to ramped-up support from Riyadh, Doha and Ankara. But the commanders here insist their recent gains, including the capture of Idlib, which is only the second provincial capital lost by Assad in this war, are not the result of outside assistance.

“What did we get from them?” sneers a rebel commander with Jaish al Fata, or the Army of Conquest, which is what the new rebel alliance began calling itself on March 28. “The Turks speak a thousand lies. Most of our weapons are those we seized from government forces or arms that were supplied by the Gulf a year and half ago. We got nothing from the Gulf or Turkey ahead of this offensive. These are our victories, no one else’s,” he insists. He asked he not to be identified by name for this article.

Islam Alloush, a spokesman for Jaysh al Islam, a rebel brigade that has good ties with the Saudis (who helped negotiate the formation of the militia originally as a counter to Jabhat al Nusra), confirms there has been no recent input of arms from outside. Asked if his brigade received new supplies from the Saudis, he says: “No we have not seen anything like that.”

And Abu Jaseem, the commander of the First Regiment, a semi-autonomous militia within Liwa al Tawhid brigade, told me over a dinner of chicken and rice and many cigarettes that he has had no arms supplies from Gulf sponsors since late 2013. “The weapons we use are those we have captured from Assad’s soldiers.”

Another insurgent commander who participated in the assault on Idlib says more advanced weapons supplied by the Americans, including TOW anti-tank missiles, are being used by brigades fighting with Jaish al Fata.

Some of these weapons had been supplied last year by the U.S. and were seized from two Washington-backed militias, Harakat al Hazm and the Syria Revolutionaries Front, which collapsed earlier this year after infighting with jihadists and Islamists. Other American-supplied weaponry is being used in the current offensive by militias still backed by Washington, including Division 13 and Fursan al Haq, which are cooperating with the new Islamist alliance but are not formally part of its command structure.

Is it possible, likely or credible that Al Qaeda affiliate Jabhat al Nusra will split with its parent organization? The success of the offensive in Idlib is adding impetus to the debate within Jabhat al Nusra about precisely that subject. Several rebel commanders and Syrian opposition figures say it is highly likely that al Nusra will soon break apart formally, roughly along the lines of local vs. foreign fighters, with the former opting out of the infamous terrorist affiliation.

“I think it will happen soon,” says Muhamed Nabih Osman, who oversees a charitable association for former Assad prisoners. “You have to understand that al Nusra consists of two very different parts and that one part, mostly local fighters, are not interested in global jihad.”

Sitting in a nondescript office in central Gaziantep, the gray-haired former electrical engineer who was imprisoned for 14 years by Assad in the notorious Tadmor jail in the deserts of eastern Syria, says most Nusra fighters see Assad as the enemy and not the West. He dismisses Western accusations that the ideology of most in the new Islamist alliance is anti-democratic and hostile to minorities.

“The West is living in detached world of philosophical ideas,” the former engineer says, speaking slowly and methodically. “They want us to conform to their ideas but we can disagree with them without being extremists. Thousands of people are getting killed and they are worried about what happens after Assad and they want to teach us about democracy and women’s rights. They don’t provide safe havens or no-fly zones for the civilians who are being slaughtered in droves. All they worry about is who controls Syria after. Syrians will.” Osman emphasizes he is not a member of any armed group but says he knows the main players in al Nusra and another powerful Islamist militia, Ahrar al Sham, and speaks with them regularly.

In recent weeks al Nusra has been recovering from the emergence of its jihadist rival ISIS, and has been attracting significant numbers of fighters again, many of them defectors from moderate and Islamist insurgent militias. Last November a convergence between al Nusra and the Islamic State appeared more likely, with efforts being made by some al Qaeda veterans to lay the groundwork for an alliance of convenience between the arch-rivals. A major meeting between leaders from both groups was held in a farmhouse west of Aleppo. Shortly after, ISIS fighters were dispatched to help—at least in a symbolic way—al Nusra fighters in battles against Western-backed bridges in Idlib.

But local fighters—who likely make up 80 percent of al Nusra—have been opposed to deal-making with ISIS and have been critical of the harsh governance methods used by some of their pro-ISIS comrades in territory controlled by al Nusra. In the ongoing internal debate al Nusra Emir Mohammed al Jawlani has so far not shown his hand, but rebel sources say he appears to be tilting towards a break with al Qaeda, which is being advocated strongly by Abu Maria al Qahtani, the commander of Nusra in Deir ez Zour.

And rebel commanders say the break-with-Al- Qaeda scenario has gained momentum since the deaths of Nusra military chief Abu Hamam al Shami and three other al Qaeda leaders last March in a Syrian airstrike on the village of Habeet near the border with Turkey. All four leaders killed were al Qaeda loyalists.

Qatari officials have been urging al Nusra’s leadership for weeks to rebrand, to sever ties with al Qaeda, and to form a new entity aligned ideologically with Islamist rebel brigades, according to rebel commanders. It may also be—with or without a green light from Washington— that the Qataris have been hinting that an al Nusra break with al Qaeda would improve the chances of persuading Western powers to impose a no-fly zone on northern Syria, something the Turks as well as Gulf Arabs are pressing for and the rebels say would deprive Assad of his one crucial battlefield advantage—airpower.

“Al Nusra commanders and fighters keep on saying they will happily break with al Qaeda, if that is a precondition for a no-fly zone,” says a Tawid field commander who enjoys good ties with al Nusra.

Whatever al Nusra finally decides, rebel commanders clearly believe the offensive in Idlib has the makings of the beginning of the end for Assad. They are not saying the end will be quick in coming but for the first time in months appear as convinced they can win as they did when they stormed into Aleppo more than two years ago and seized nearly half of Syria’s commercial capital.

Much of their sudden confidence can be put down to buoyancy that a battlefield victory brings. U.S. officials argue Idlib just marks another twist in the seesawing war that has left more than 200,000 dead and ten million Syrians displaced. But the map now looks different from at the end of last year. In retrospect insurgent commanders now agree Aleppo was a false dawn and that the northern rebel brigades got bogged down in the city at enormous cost in terms of morale and casualties when they should have been more mobile and picking off smaller and winnable prizes such as Idlib or Hama.

Few commanders I have spoken with in the last few days believe the new Islamist alliance should now turn towards Aleppo. Even commanders based in Aleppo think that would be a strategic mistake. “No, the focus should now be on Latakia,” says the First Regiment emir Abu Jaseem over our chicken-and-rice dinner in an apartment on the outskirts of Gaziantep.

A slight dark-skinned 43-year-old, Abu Jaseem argues that striking towards Latakia, populated mostly by members of Assad’s minority Alawi Muslim sect, an offshoot of Shia Islam, would send a symbolic, unsettling message to the regime’s supporters—namely that the war is coming in earnest to their traditional homeland and that they should give up the idea that they can carve out a coastal Alawi rump state around Latakia and Tartous if the war goes against Assad and the rebels ever manage to seize Damascus.

What rebel commanders have noticed in recent weeks is that disputes appear to be flaring among Assad’s defenders when Alawi villages and towns are attacked: Syrian army regulars are at odds with the mostly Alawi self-protection forces grouped in the National Defense Forces and also with Shia volunteers from Iran and Lebanon’s radical Shia movement Hezbollah.

In Idlib in the final days of the rebel assault insurgents attacked Alawi villages outside the city, mainly as a feint, and when they did so it triggered sharp disagreements between the NDF commanders, who argued they should rush to defend the Alawi settlements, and regular army commanders, who wanted to stay put. With rebel gains, friction and in one case clashes between Alawi militiamen and army regulars flared elsewhere in northern Syria, too.

At the dinner, another rebel commander who fought alongside Jaish al Fata in Idlib and is in the process of moving most of his militia from Aleppo to join the Islamist alliance disagrees with striking at Latakia and argues the strike should be towards Hama and then on to Damascus to assist the southern rebels, although he acknowledges that the war will not finally end until the mainly Alawi coastal cities of Tartous and Latakia have fallen.

Seizing Hama, he says, would also be of great symbolic value. “This was where Assad’s father killed thousands,” he adds, referring to crushing of a Muslim Brotherhood uprising in 1982. “The son is driven by what his father did and has always believed he can emulate his father—capturing Hama would demonstrate he can’t.”

The debate playing out at the dinner is one the top field commanders of the Islamist alliance are having now—west to the coast or south towards Hama and then Damascus. Before they make a final decision there remains unfinished business nearer at hand. Jaish al Fata forces are now attacking the villages of Ariha and Mastouma south of Idlib and Ankawi and Ghab south of Jisr al Shughour in order to sever the M4 highway linking Latakia to Idlib and Aleppo. These attacks are forcing Syrian government units to defend a 30-mile W-shaped line—a precarious military position.

The rebels’ firm belief is that by switching the axis of the northern theater away from Aleppo they have managed to transform the war. If they can notch up more gains with few casualties, the new Islamist alliance appears likely to remain and not go the way of previous alliances that fell apart in a matter of weeks amid rebel infighting. “I think it will last,” says Mohammed, a rebel commander who once worked at the center of a rebel alliance in Aleppo. “I have not seen this level of coordination and trust before.”

While U.S. officials seem ready to dismiss this as another false dawn, one former American ambassador isn’t so skeptical. “Despite constant Western media assessments that Assad’s situation is secure, the reality is that the Syrian war is one of attrition,” according to a paper by former U.S. Ambassador to Damascus Robert Ford at the Washington-based Middle East Institute. “And minority regimes usually do not fare well in prolonged wars of attrition.”

Sitting over dinner, Abu Jaseem pulls on yet another cigarette and says that once again fighters are discussing what the future of Syria will be when this long nightmare of fighting and blood and friends dying in your arms finally is over. “Syria will be a Muslim country,” he says, adding hopefully, “But not too Islamic.”