Some analysts swiftly labeled the shooting down of the Syrian plane as the de facto establishment of a US-enforced no-fly zone for the chunky slice of northern Syria that is under YPG control. Barzan Iso, a Syrian Kurdish journalist and Al-Monitor contributor, said this hopeful interpretation was shared by thousands of Syrian Kurds. “Video footage of the downing of the plane has spread like wildfire,” he said in a telephone interview. "Many people are celebrating."

The Syrian Kurdish People’s Protection Units (YPG) forms the strategic core of the US-armed cocktail of Kurds and assorted Arabs who are fighting to liberate Raqqa , the so-called capital of the Islamic State.

The Pentagon said it had resorted to downing the Syrian Su-22 in self-defense after it ignored repeated coalition warnings conveyed through a de-confliction channel with the Russians and dropped several bombs near the American-backed militia known as the Syrian Democratic Forces (SDF) in the western Raqqa countryside.

On the face of things, the United States was reacting to what it termed regime aggression against its local Kurdish and Arab partners.

The United States on Sunday shot down a Syrian fighter jet for the first time since the start of Syria’s chaotic civil war in 2011. The action has intensified speculation about the risks of direct confrontation between the United States and the regime of Syrian President Bashar al-Assad and more alarmingly, with his chief mentors Russia and Iran. While such fears may prove exaggerated, the move could have momentous and potentially dangerous consequences for Syria’s Kurds.

The Syrian government angrily disputed the American version of what had transpired. It insisted that its pilot was flying a mission against IS, not the SDF. Russia struck a similarly belligerent tone, calling the US response “a flagrant violation of international law" and threatening to treat coalition planes as potential targets if they ventured west of the Euphrates River. Under the terms of an informal agreement with the Russians, coalition planes have largely confined their operations to the east and northeast of the river.

But as IS gets rolled back and the SDF and the regime race to fill the void, those lines are beginning to blur. The more land the SDF grabs, the greater its bargaining position during future talks for a political settlement. The Syrian jet was struck down near the ancient town of Rusafa, which lies to the south of the Euphrates.

Ceng Sagnic, the coordinator of the Kurdish studies program at the Dayan Center in Tel Aviv, observed in a tweet, “It doesn’t matter whether the [Syrian] jet hit the YPG or IS. In both cases, the YPG’s zone of influence was being protected.” He went on, “A simple definition of this is a ‘no-fly zone.’ No-fly zones amount to de facto partitioning, and the best example of this is 1991 Iraq.”

Sagnic was referring to when the US-led allies declared twin no-fly zones over northern and southern Iraq to protect the country’s Kurds and Shiites from further attack by Saddam Hussein’s forces, culminating in the Iraqi dictator’s ejection in 2003. Under the US security umbrella, the Iraqi Kurds ran their own affairs for the first time, laying the foundations for their long-nurtured dreams of independence.

The official US policy was never to dismember Iraq, but to overthrow Saddam. Similarly, in Syria, the goal is not regime change but to defeat IS. Yet, US intervention in both countries has had dramatic if unintended effects.

The unraveling of central authority and the rise of IS have presented the Kurds on both sides of the border with unforeseen opportunities. The Iraqi Kurds are planning to hold a popular referendum on independence Sept. 25. It will encompass the so-called disputed territories, including the oil-rich province of Kirkuk, which fell under Iraqi Kurdish control when the Iraqi government forces chose to withdraw rather than fight advancing IS militants.

In Syria, thanks to US air support and the YPG’s battlefield prowess and political smarts, the Kurds control around a fifth of the country, a third of its oil, half of its wheat and three of its largest dams, producing nearly all of its electricity. It’s easy to see why they would want to replicate Iraqi Kurdistan’s success and how Sunday’s downing of the Syrian jet could feed such hopes.

Aaron Stein, a senior fellow at the Atlantic Council who studies the Syrian conflict, told Al-Monitor, “The YPG is creating facts on the ground that could, could conceivably help them to win concessions from the regime or Russia, assuming they retain some level of support from the US.”

It’s not so much the level but rather the nature of US support that remains the big problem. Unlike their Iraqi brethren, the pro-YPG Kurds have yet to be treated as political actors by the United States, and unlike other members of the Syrian opposition, have not been granted seat at the UN-sponsored Geneva peace talks to end the Syrian war.

One of the main reasons for US skittishness is its prized if increasingly difficult NATO ally, Turkey. The Turks insist that the YPG is a terrorist group and poses a threat to its national security. Turkey’s borders with the Kurdish-controlled parts of northern Syria remains firmly sealed. Western humanitarian relief organizations that operate out of Turkey and inside the Kurdish zones are being shuttered.

Turkish ire stems from the YPG’s intimate links with the Kurdistan Workers Party (PKK), the Kurdish guerrilla outfit that has been fighting for Kurdish self-rule inside Turkey since 1984. The YPG claims that it is not connected, and the United States pretends to believe it. Yet the YPG openly pledges fealty to PKK leader Abdullah Ocalan, who is stuck in a Turkish jail. The idea of a PKK-led statelet on their border drives Turkish leaders of all stripes berserk.

In August 2016, Turkey sent its troops into the Syrian town of Jarablus to clear its borders of remaining pockets of IS, but more importantly, to prevent the YPG from getting there first and creating an uninterrupted stretch of territory from the Iraqi border all the way to Afrin. Linking up its northeastern domains with this mainly Kurdish enclave to the west of the Euphrates is of huge symbolic and strategic importance to the YPG. Its efforts to do so have been repeatedly frustrated.

On March 17, 2016, as the areas wrested from IS began to encompass non-Kurdish majority towns like Tell Abyad, the pro-YPG-dominated administration declared the creation of a “Democratic Federal System of Northern Syria.” With its emphasis on communal rule, gender equality and fair representation for all of Syria’s ethnic and religious groups, the federation is being touted as a blueprint for future governance for the country. It also sends a clear message that the Kurds have no intentions of splitting away.

Aliza Marcus, the author of "Blood and Belief, the PKK and the Kurdish Fight for Independence,” told Al-Monitor, “I don’t think the dream of independence is gone among the PKK’s supporters.” They include tens of thousands of Syrian Kurds who venerate Ocalan. Yet, Marcus explained, “The PKK has made clear over and over again that it's not striving for an independent state, but that it does want broad freedoms and rights for Kurds in the region."

Ilham Ahmed, the steely co-chair of the Syrian Democratic Council and a roving ambassador of sorts for the YPG, told Al-Monitor during a recent interview in Washington, “The conditions for an independent Kurdish state do not exist in Syria.” This, she explained matter-of-factly, is because, “As Kurds, we have too many enemies.” And Turkey, which runs the length of flat and landlocked Rojava’s northern borders, and more critically still controls the flow of both the Euphrates and the Tigris rivers, tops the list.

The YPG has repeatedly said it wants friendly relations with Turkey and has exercised exceptional restraint in the face of continued Turkish attacks, even after Turkish planes rained bombs on YPG targets near the town of Derik on April 25, killing at least 20 people.

In a show of solidarity, US special forces deployed to the Turkish border and the Turkish attacks on areas where the Americans are known to operate have ceased.

But the United States continues to deny the Syrian Kurds the slightest hint of political legitimacy. This has given rise to growing debate within YPG circles as to why they should be helping the United States capture Raqqa, a mainly Arab city, at all. The battle has proceeded with unexpected ease but SDF casualties, including Kurdish ones, are bound to mount. Will it be worth the sacrifice?

Ahmed reckons that it will. “The Americans have not promised us anything,” she said. “But for as long as the Americans remain in Syria and its policy is open ended, our relationship offers opportunities worth investing in.” At the same time, freeing Raqqa cements cooperation between Arabs and Kurds that could prove useful in any future political talks.

Stein concurs. “The YPG should look to take as much territory as possible and keep working with the United States. The US special operations forces are going to be in northeastern Syria for years to come. We are going to see an incremental increase in the State Department presence as well.”

Stein was alluding to State Department plans to expand the tiny contingent of its diplomats and USAID staff in the Kurdish-controlled region to help with stabilization efforts in Raqqa. Administration sources stress that none of this amounts to governance or nation-building but rather ensuring that the citizens of Raqqa remain safe and have access to basic amenities on the day after.

Some point out that the United States launched Operation Provide Comfort in Iraqi Kurdistan in 1991 with similarly meager goals.

To be sure, ever since the Donald Trump administration took over in January, tensions between the US-led coalition and the regime and its Russian and Iranian allies have been growing. Today, the Pentagon confirmed that it shot down an armed Iranian drone near al-Tanf, the southern desert outpost near the Jordanian border where the coalition is training Syrian rebels. The incident marks the fifth time since late May the US military has bombed pro-Syrian forces in the area and could well signal further escalation of a kind that could ultimately benefit Syria’s Kurds — or not.

Each time the United States defends its Syrian Kurdish partners militarily its moral obligation to keep doing so grows exponentially. Through its actions, the United States is effectively pitting the Syrian Kurds against Turkey and the regime and now against Russia as well.

The Syrian Kurds owe much of their success to their ability to leverage their alliance with the Americans to extract concessions from the regime and the Russians. Such gains remained possible as long as the Americans, the Russians and the regime agreed to stick to their mutually agreed zones of influence. That they no longer are is upending the YPG's delicate balancing act.

The first signs of American encroachment began in August 2016, when the SDF captured the mainly Arab town of Manbij, west of the Euphrates. The move enraged Turkey, which until then seemed sullenly resigned to the US-YPG relationship provided that it remained east of the Euphrates. Soon after, Russia agreed to let Turkish troops intervene in Jarablus and push all the way to the town of al-Bab.

In a sign of the fraying relationship between Moscow and the YPG, Ahmed accused Russia of ganging up with Iran against the Syrian Kurds and of wielding the threat of Turkish intervention to blackmail the YPG into letting regime forces retake territory around Afrin. “Forcing the Kurds to accept regime rule would be a historic cruelty,” she wrote for the pro-Kurdish Özgürlükçü Demokrasi newspaper.

So would making promises that cannot be delivered.

Amanda Sloat, a deputy assistant secretary of state in the Barack Obama administration who dealt with Turkey, is a well-known critic of prioritizing short-term military tactics against IS without an accompanying long-term political strategy for Syria. She told Al-Monitor, “The Trump administration should be transparent with Syrian Kurds — as well as Syrian Arabs, Turkey and other regional partners — about what it will support in a post-IS Syria. Hopefully it is conveying opposition to an independent state and refraining from any hint of political recognition in exchange for military action.”

Meanwhile, the Syrian Kurds, as Stein noted, will continue to create their own facts on the ground.

Correction: June 20, 2017. A previous version of this article quoted Ilham Ahmed's words from a news source identified as Demokrat Haber, when in fact it was from Özgürlükçü Demokrasi. Al-Monitor regrets the error.