Turkey’s 2017 purchase of Russia’s S-400 missile defense system made it a pariah on Capitol Hill, causing Congress to lead the way in throwing Ankara out of the F-35 stealth fighter jet program.

However, Turkey’s backing for Ukraine, most notably through the supply of armed drones and diplomacy with Russia, has provided Ankara with a chance to improve its image in Congress. If it plays its cards properly, the NATO ally may be able to persuade Congress to approve a $6 billion purchase of 40 Lockheed Martin Block 70 F-16 fighter planes and around 80 modernization kits to modernize its existing fleet.

Several important congressmen who were influential in removing Turkey from the F-35 program have tentatively indicated to Defense News that they may be willing to allow Ankara to acquire the F-16s after the Biden administration stated that such a deal may benefit NATO and US security interests.

Nonetheless, Congress has significant veto power over potential arms sales, and lawmakers made it clear that an F-16 transfer would be contingent on Turkey continuing to support Ukraine even as it tries to strike a delicate balance in its relations with both the US and Russia amid a slew of other regional disputes.

“We need to talk and work with Turkey and others that are working with us against Russia,” House Foreign Affairs Committee Chairman Gregory Meeks, D-N.Y., told Defense News. “They’ve shown some movements in the right direction. There’s other things that we still need to work with Turkey, certain things that still irritate us at times.”

Meeks did not take over as head of the Foreign Affairs Committee — a post that permits him to veto arms deals – until 2021, long after Congress initially enshrined Turkey’s ejection from the F-35 program in the 2019 government spending bill.

Other Democrats and Republicans who battled tooth and nail to keep Turkey out of the program have also indicated that they will not use their influence to prevent a future F-16 sale.

“I’ve talked to several of the parties involved in this,” Sen. James Risch, R-Idaho, the ranking member of the Foreign Relations Committee, told Defense News. “The Turks have made a credible argument for why they should get the F-16s.”

“I’m positively disposed in that direction, but I’m not completely there yet,” he added.

Since the 1980s, Turkey has continually maintained a fleet of outdated F-16s while Ankara pursues an upgrade.

Risch also stated that enabling Turkey to obtain F-16s is a “different case” from allowing Turkey to receive F-35s.

Washington halted the supply of modern F-35 fighter fighters to its NATO member because of concern that Russia might use the S-400′s formidable radar system to spy on the cutting-edge aircraft, jeopardizing the technology.

The S-400 acquisition also caused the US to penalize Turkey’s military procurement agency in 2020, as required under Russia sanctions legislation. However, in recent years, President Recep Tayyip Erdogan has pursued a détente with Turkey’s NATO partners.

“We expect Turkey to continue standing with its NATO allies who are in lockstep in supporting Ukraine as it defends its homeland.” said the office of Rep. Mike McCaul, R-Texas, the ranking member of the House Foreign Affairs Committee.

“The war in Ukraine is not over,” McCaul’s office said. “We expect that should the administration seek congressional authorization for this sale, Turkey will still be playing a constructive role in the conflict, but also addressing concerns over Turkey’s role in other global conflicts.”

At home, Erdogan has portrayed his campaign for the F-16 sale as prospective recompense for Turkey’s sunk investments as a result of its ejection from the F-35 co-production program. And, during a meeting last October, he pressed Biden on the transaction.