US senators declined on Thursday to block the sale of F-16s to Turkey, despite voicing deep disdain for Ankara's conduct as an ally.
They were upholding an unofficial bargain that Turkey would get the fighter jets if it stopped blocking Sweden's accession to Nato.
“A deal's a deal,” said Idaho's Jim Risch, the ranking Republican on the Senate foreign relations committee.
Kentucky Republican Rand Paul, who introduced the resolution to try to block the sale, told fellow senators: “Call it quid pro quo. That sounds better than extortion.”
The Senate voted 13 to 79 to reject Mr Paul's proposal.
Along with the Democratic committee chairman, Ben Cardin of Maryland, Mr Risch took the Senate floor before the vote to acknowledge some of the many US objections to Turkish President Recep Tayyip Erdogan's government.
They include its attacks on America's Kurdish allies in Syria, its backing for offensives by Azerbaijan on the ethnic Armenian enclave of Nagorno-Karabakh, and Turkey's deal with Russia to buy its S400 missile defence system and other matters.
But the Republican and Democratic senior foreign policy leaders said adding Sweden to Nato was too important to the overall strategic interests of the western military alliance.
Sweden, along with Finland, sought to join Nato after Russia's 2022 invasion of Ukraine.
The US and the majority of other Nato allies supported the accession, saying the two countries' militaries, industries and locations near or bordering Russia would strengthen the alliance.
Finland joined Nato last year after Mr Erdogan lifted initial objections to that country as well.
His objections to Sweden included it offering refuge to Turkish critics in exile.
But he also publicly linked his objections to hopes of overcoming US reluctance to sell Turkey new models of the advanced fighter jet.
“I’m not here to defend Turkey or the other things that they do,” Mr Risch said. “What I am here to do is defend the importance of Nato.”
Mr Paul said before the vote that continuing to withhold the advanced fighter jets was the best thing the US had to influence Turkey's behaviour as an ally.
“What will Turkey do next time they want something?” he asked.
The State Department notified Congress of its approval of the $23 billion F-16 sale to Turkey in January, along with a companion $8.6 billion sale of advanced F-35 fighter jets to Greece.
The State Department agreement came hours after Turkey deposited its “instrument of ratification” for Sweden’s accession to Nato with Washington, which is the repository for alliance documents, and after several key members of Congress lifted their objections.
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