US President Donald Trump's close personal relationship with Turkish President Recep Tayyip Erdogan is expected to take centre stage at next week's NATO summit in Turkey, where the Republican leader is also hinting at major defence announcements that could reshape bilateral ties.
Erdogan successfully persuaded Trump to attend the summit in Ankara after a personal appeal, securing the US president's presence at a time when Washington's commitment to NATO has been under increasing scrutiny.
"I would not have gone for most people," Trump said last week. "But he called me up. He said: 'Please, I have it in Turkey. You got to be there. The United States has to be in there.' And so I'm going out of respect to President Erdogan."
Trump's attendance comes despite his often combative relationship with several European allies. He has repeatedly criticised NATO members over defence spending, threatened to reduce the US military presence in Europe and recently clashed with allies over their reluctance to support his military campaign against Iran.
Analysts say Erdogan has capitalised on his longstanding rapport with Trump to reinforce Turkey's position within the alliance.
Trump has frequently praised Erdogan, describing him as "a hell of a leader" and a close friend.
Philip Gordon, who served as national security adviser to former Vice-President Kamala Harris and is now at the Brookings Institution, said Trump's affinity for powerful leaders helps explain the relationship.
"His relationship with Erdogan, which is pretty strong, is consistent with what seems to be a pattern of his preference," Gordon said.
"It has often been pointed out he seems to have better relationships with adversaries and autocrats, and he certainly says nicer things about them than with allies."
"Erdogan is taking full advantage of it," he added.
Trump is expected to hold bilateral talks with Erdogan on the sidelines of the summit, becoming the first US president to visit Turkey since Barack Obama's trip in 2015.
Relations between Ankara and Washington had cooled considerably during Joe Biden's presidency over concerns about Turkey's democratic backsliding and its close ties with Russia.
Opposition parties and human rights organisations have accused Erdogan's government of undermining democratic institutions, restricting freedom of expression and pursuing politically motivated prosecutions against journalists, activists and opposition figures.
Trump has also hinted that his visit could include significant announcements on defence cooperation.
Asked whether he would bring "a big gift bag for Erdogan", including approval for F-110 jet engines and F-35 fighter aircraft, Trump replied: "Yeah, I think so. I'm going to probably do something that's going to make him very happy."
Turkey was removed from the US-led F-35 fighter jet programme in 2019 after purchasing Russian-made S-400 air defence systems. Washington argued that operating the Russian system alongside the stealth aircraft could compromise sensitive military technology.
During a recent Oval Office meeting, Vice-President JD Vance confirmed that the administration was exploring ways to resume F-35 sales, provided Turkey complied with US legal requirements.
However, any deal is expected to face strong bipartisan opposition in Congress, particularly while Ankara retains the Russian missile defence system.
Turkey is also seeking to purchase F-110 jet engines to power its domestically developed KAAN fighter aircraft.
According to US officials, the State Department recently notified Congress of plans to move ahead with more than US$700 million in engine sales despite anticipated opposition.
Representative Gregory Meeks, the senior Democrat on the House Foreign Affairs Committee, criticised the decision, saying the administration had failed to adequately explain the proposed sale or address concerns over Turkey's continued possession of the S-400 system.
The improvement in bilateral ties extends beyond defence.
Earlier this year, the US Justice Department dropped its long-running case against Turkey's state-owned Halkbank, which had been accused of helping Iran evade American sanctions.
Trump has also appointed longtime ally Tom Barrack as US ambassador to Turkey.
Ahmet Kasim Han, professor of international relations at Ankara's TED University, said Barrack has become an important facilitator in the relationship between the two leaders.
Erdogan and Trump have maintained frequent telephone contact, discussing issues including Syria, Gaza and broader Middle East security.
Turkey also joined Trump's Board of Peace initiative established to oversee the Gaza ceasefire.
Trump recently claimed he had asked Erdogan to stay out of the conflict with Iran and that the Turkish leader had complied, although there has been no indication that Ankara intended to become directly involved.
The strength of the relationship was also evident during a joint appearance with Israeli Prime Minister Benjamin Netanyahu last year.
While Netanyahu sought US backing against growing Turkish influence in Syria, Trump instead praised Erdogan and urged the Israeli leader to be "reasonable".
Following last year's NATO summit in The Hague, Erdogan highlighted the ease of communication between the two leaders.
"With my friend Trump, we are opening the door to a new era in Turkish-American relations," he said.
"The process of telephone diplomacy between us has never exceeded 24 hours. When we call, the other side responds within 24 hours."