KOBANI, Syria — The secret military base here is the epicenter of a four-year-old U.S.-led war against the Islamic State that American commanders say has succeeded in killing nearly 65,000 fighters.
But just as the terrorist group looks to be on the brink of defeat, senior officials worry that their efforts will be wasted.
Some U.S. commanders say what they perceive as a lack of guidance from the White House — which sent Secretary of State Rex Tillerson and National Security Adviser H.R. McMaster packing in a 9-day span — is threatening their mission to destroy ISIS. Cracks are showing in America's alliance with the Kurds of northern Syria, who question whether they can rely on the U.S. under President Donald Trump.
"We're on the two-yard line. We could literally fall into the end zone. We're that close to total victory, to whipping out the ISIS caliphate in Syria," one U.S. special forces commander told NBC News. "We're that close and now, it's coming apart."
More than a half-dozen senior officials interviewed by NBC News shared the commander's views.
The hours of interviews revealed a profound sense of frustration, bordering on anger. NBC News agreed not to reveal the officials' identities because they were not authorized to discuss U.S. policy in Syria publicly.
There are roughly 2,000 U.S. troops in the country, and NBC News was granted extensive access to the anti-ISIS mission there.
More on MSNBC's "On Assignment with Richard Engel" on Friday at 9 p.m. ET
"We send memos. We tell them [the White House] what is going on. I'm not sure they're listening, or if they even know what we're doing out here," another commander said. "I don't think anyone is home right now."
In a speech on Thursday, Trump said the U.S. would be "coming out of Syria, like, very soon."
He added: "Let the other people take care of it now."
The White House did not respond to a request for comment.
Ten weeks ago, U.S. military officials were confident that ISIS would be defeated within 90 days. But that optimistic prediction was made before Turkey launched an offensive into the Kurdish enclave of Afrin in northwest Syria in late January — a move that has further scrambled the geopolitics of the region.
Turkey's incursion prompted Kurdish fighters in the eastern part of the country, where they had been fighting ISIS alongside U.S. special forces, to redeploy westward. With its principal ally now under attack by Turkey and distracted, the U.S. military announced an "operational pause" to its anti-ISIS fight in late March.
The concern is that ISIS may now reclaim some of its lost territory, or that fighters allied with Syrian President Bashar al-Assad may take advantage of U.S. forces' weakened defensive position. A recent attack on a U.S. base near Deir ez-Zor by pro-regime fighters and Russian mercenaries underscored that risk.
Four years ago, ISIS swept across Syria and Iraq, capturing a territory the size of a small European country with oil fields and a population of roughly eight million.
The group's caliphate became a base for murderous extremists to plot terrorist attacks abroad. It was an execution ground for hostages, including Americans, and a training ground for thousands of foreign fighters.
The counter-ISIS mission was somewhat straightforward in Iraq. American troops trained and re-equipped the Iraqi army so that with significant U.S. assistance, local forces eventually pushed ISIS out.
Things were for more complicated in Syria where a civil war has now entered its seventh year.
The U.S. has experimented with a variety of policies, supporting a myriad of fighters who have nearly all proven to be unreliable; the opposition groups argue that Washington never gave them enough support to succeed.
But one group has exceeded expectations: the Kurds.
"I'm very impressed. These people stood up without any international support," said Gen. Jonathan Braga, the operations director of Operation Inherent Resolve, the official name for the U.S.-led war on ISIS. "I was inspired and I was impressed."
U.S. military officials explained that the Kurds, unlike most of the Arab militias the U.S. had been supporting, kept their promises and communicated well with American forces.
"It's the partnership we wished for, but never had," said one commander who is in daily contact with the Kurdish-led forces.
Culturally and organizationally, the Kurds were different too. They could account for every weapon they were given, and they weren't religious extremists. Women fight in near-equal numbers to men.
"Women fighting formations — I mean not in a support role, not in a logistics role — on the front line killing ISIS. That's a pretty amazing story to me," Braga said. "That's the commitment level. They trusted our first forces on the ground and we trusted them."
U.S. special forces and their Kurdish allies wrote the rulebook as they went.
One U.S. commander recounted how they marched sheep over terrain to see if it was mined, and rolled tires down streets to test for improvised explosives. The initial 50 American special forces grew to the current 2,000.
Arabs joined the Kurds in a coalition known as the Syrian Democratic Forces (SDF), numbering 60,000.
U.S. troops directed airpower and surveillance, while their partners cleared the ground with small arms, light machine guns, and a few recycled Humvees.
One high-ranking U.S. commander said that were it not for this alliance, 60,000 U.S. troops would have had to deploy to Syria each year to produce a similar result, undoubtedly resulting in American casualties.
So far, one U.S. soldier has been killed in combat in Syria throughout the anti-ISIS campaign, according to a U.S. military spokesman. More than 4,000 members of the SDF have died.
The coalition announced Friday that two personnel in Syria had been killed and five wounded in a blast from an improvised explosive device late Thursday, but would not provide their nationalities when asked.
"We have been abandoned and betrayed."
Braga was careful not to question U.S. policy or his orders, but did say the Kurdish-led SDF deserves recognition. "I think the world owes them a debt of gratitude. They were the first to stand up against [ISIS]."
But Kurdish goodwill toward the U.S. has frayed given what many see as Washington's indifference to the Turkish offensive in Afrin.
Turkey's assertive posture stems from the fact that it considers Kurdish separatism a national security threat. It sees the Kurdish fighters in northern Syria — known as the People's Protection Units, or YPG — as an extension of the Kurdistan Workers' Party, or PKK, a separatist group operating within its own borders. Both Turkey and the U.S. have labeled the PKK a terrorist organization.
Around 15 million Kurds live in Turkey just across the Syrian border. The government in Ankara worries Syrian Kurds will inspire Turkish Kurds to demand more rights, potentially breaking Turkey apart.
If Turkey and its Syrian rebel allies push just 60 miles east from Afrin to the city of Manbij, they would also run up against U.S. special forces there — potentially setting up a once-unthinkable confrontation between two NATO allies.
This tension, coupled with the White House's lack of focus on foreign policy and the recent departures of Tillerson and McMaster, is causing the war on ISIS to falter, according to the top U.S. commanders in northern Syria.
The leaders of the Kurdish-led force are begging their American partners — and after so many years their personal friends in some cases — for protection from Turkey. So far the U.S. military has not come to their rescue.
"We have been abandoned and betrayed. We were useful to fight against ISIS, but the Americans are now turning their backs on us," said Mohammed Mustafa Ali, a commander of the Kurdish-led force in Manbij.
The head of the SDF, a Kurdish commander known as Gen. Maslum Abdi, called the lack of American support "an insult to the resistance we showed."
U.S. officials say they don't have the authority to push back against Turkey with force, even though Turkey is attacking their anti-ISIS partner.
As Turkey intensifies its advance, some Kurdish fighters have begun abandoning their positions set up to confront ISIS so they can fight Turkey.
If ISIS regains ground, "the world will will pay a price," Braga warned. "So I don't think we can go backwards. I don't even want to contemplate that future. That's not a world I want to live in."
Richard Engel reported from Kobani, Syria, and Kennett Werner from London.