ISTANBUL - With U.S.-Turkish relations at their lowest ebb in decades, the future of a critical American air base in Turkey is increasingly in the spotlight.
The vast Incirlik Air Base, located in southern Turkey close to Syria, has been a longstanding symbol of U.S.-Turkish cooperation. At the height of the Cold War, it underscored America's commitment to its NATO partner against the Soviet Union.
"We have to underline the Incirlik is one of the most important bases in the Middle East with the placement of tactical nuclear weapons at the base," said professor Mesut Casin, a Turkish presidential foreign policy adviser. "This shows Turkey continues to support the value of the NATO organization."
It's widely reported that the United States retains around 50 nuclear free-fall bombs at the facility. During the Cold War, the weapons were relied on to deter vast Soviet ground forces massed on the Turkish border.
However, with Ankara and Washington at loggerheads over a myriad of issues, including Turkey's deepening ties with Russia and the removal of Turkey from a U.S. jet fighter program, the future of Incirlik is increasingly murky.
The Countering Turkish Aggression Act, a bipartisan bill under consideration in the U.S. Senate, would require the Trump administration to consider alternative bases for "personnel and assets" deployed at Incirlik. The bill comes in response to Ankara's offensive into Syria against a Kurdish militia, which is an ally in Washington's war against Islamic State.
House Armed Services Committee member Representative Kendra Horn tweeted last month that she is "deeply concerned that strategic nuclear weapons remain on an air base within Turkish borders." Horn later removed the tweet.
"They (Congress) are talking about removing the nuclear arsenal from Incirlik," said former Turkish ambassador Mithat Rende. "If they (nuclear weapons) are removed, that would be a sign of a huge lack of confidence (by Washington in Ankara)."
"There would be a trust problem, and relations might unravel if you withdraw the nuclear arsenal from Turkey," he added. "And you would expect an overreaction from the Turkish side if the U.S. pulls out its nuclear arsenal."
"Turkey-U.S. relations cannot continue in this climate of threats," warns Casin. "Turkey has a long history of being the United States' best ally in the region. Who is the winner of this present situation, Russia and China."
Analysts warn Moscow will be eager to take advantage of any U.S. reduction in Incirlik.
"If the Americans take their nuclear weapons, then I can tell you if they do, then the Turks will take Russian missiles there," said international relations professor Huseyin Bagci of Ankara's Middle East Technical University. "Then the Russians will have much more free hand to gain Turkey. So the architect of a lost Turkey will be American policy, and the winner will be (Russian President Vladimir) Putin."
"Turkey is not on the defensive anymore," he added." The more the Americans make pressure, the more Turkey will work closely with Russia -- this is a historical change in Turkish foreign policy."
Russian President Vladimir Putin has carefully cultivated a relationship with Turkish President Recep Tayyip Erdogan, as relations with Ankara's traditional western allies deteriorate.
While Incirlik has been pivotal to U.S. strategic operations, including a significant withdrawal of forces from Afghanistan and Iraq, Ankara's imposing restrictions on the base's use in Syrian operations is, analysts say, a point of tension.
Last month's American operation to kill Islamic State leader Abu Bakr al-Baghdadi in Syria saw U.S. forces use a base in Iraq instead of the much closer Incirlik, requiring a round trip of many hours.
Other allies, too, have expressed frustration about Turkish operational demands. In 2017, Germany removed its forces from Incirlik because of a diplomatic spat with Ankara, relocating to Jordan.
American armed forces appear to be already taking steps to diversify their dependence on Incirlik. The U.S. has spent over $150 million in the last two years improving Jordan's Muwaffaq Salti Air Base, while American bases are reportedly being considered to be established in Turkey's neighbors, Greece and Cyprus.
Observers claim, given Incirlik's size and location, no base in the region can replace it. But Washington could be calculating that a combination of bases across the region could provide a patchwork alternative to Incirlik.
Such efforts are likely to continue, given a continued current downward spiral in U.S.-Turkish relations. However, analysts warn, abandoning Incirlik will not be without consequences.
"So American has to choose between losing Turkey or not losing Turkey. At the moment, they are more intending to lose Turkey," said Bagci.