In 2015, Sen. Lindsey Graham called Donald Trump a «jackass» and warned Republicans that nominating him would be a disaster. Trump responded by reading Graham’s personal cellphone number aloud during a campaign rally, encouraging supporters to call the South Carolina senator.

Few political rivalries seemed less likely to evolve into one of Washington’s most consequential foreign policy partnerships.

Trump rose to power promising to end America’s «endless wars» and challenging decades of Republican foreign policy orthodoxy. Graham, by contrast, remained throughout his three decades in public service an unabashed advocate of projecting American power abroad.

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Yet over the next decade, Graham became one of the few lawmakers with regular access to President Trump on questions of national security, emerging as one of the Republican Party’s most influential voices on Iran, Ukraine, Israel and NATO.

He had built his Senate career around foreign policy. While many lawmakers spent weekends back home, Graham was often overseas meeting presidents, visiting war zones and trying to broker agreements between allies and the White House. 

By the end of his career, his office had become an unofficial waypoint for foreign leaders trying to understand — or influence — the Trump administration.

In interviews following the senator’s sudden death Saturday, Trump described Graham as «like a member of the family» and said he was among the final people to speak with the South Carolina Republican after he returned from Ukraine just hours before his death.

As Trump reshaped Republican foreign policy around an «America First» agenda, Graham became one of the few congressional voices with regular access to the president on questions of war and peace. He frequently pressed Trump to maintain a muscular U.S. role abroad — even as the president questioned long-standing alliances and warned against prolonged military interventions.

Donald Trump and Lindsey Graham pose for a picture on a golf course June 28, 2025. (Sen. Lindsey Graham via X)

Rather than becoming another Republican hawk sidelined by Trump’s ascent, Graham cultivated one of the closest working relationships with the president, giving him unusual influence as the administration navigated conflicts from Ukraine and Iran to Israel and NATO.

Whether Graham simply reinforced Trump’s instincts — or helped shape them — may become one of the defining questions of his foreign policy legacy.

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«He would call me all the time,» Trump told Fox News Monday. «I’d say, ‘Stop calling me, Lindsey.’ It was amazing. He just never stopped. He was a worker — a total workaholic politician.»

Colleagues said Graham lived and breathed the work of the Senate, particularly serving as an informal envoy between the U.S. and allies around the world.

In the hours before his death, Graham told a confidant he wasn’t feeling well but joked he couldn’t die now because he still had work to do. He was preparing to push a long-stalled bipartisan Russia sanctions bill through the Senate, remained focused on advancing Saudi-Israel normalization and believed the Trump administration had not yet finished confronting Iran.

He had just completed his 10th trip to Ukraine, and maintained tight relationships not only with President Volodymyr Zelenskyy but also with Israeli Prime Minister Benjamin Netanyahu, NATO Secretary-General Mark Rutte, Gulf leaders and others around the world.

Graham believed that influence came from showing up, according to Jack Keane, a retired Army four-star general, the chairman of the Institute for the Study of War and Fox News Senior Strategic Analyst.

«He wasn’t interested in writing op-ed pieces or making speeches, he wanted firsthand contact with leaders of the world.» Keane, who counted Graham as a friend, told Fox News Digital. «He was interested in getting the results.»

Graham, upon being beaten by Trump in the 2016 primary, conceded that the then-real estate mogul understood the American public better than he did .

«He understood the American people better than we did, and shame on us for not doing it as effectively as him,» Graham said at the time, according to Keane. 

So Graham went to work making himself useful for the president.

«Graham knew the world better than almost anyone in Washington, and he likely knew many foreign leaders better than President Trump’s own appointees,» Keane said. «He made a conscious decision to help the president by offering advice and counsel, which grew into both a personal and professional relationship.»

Graham’s worldview was shaped alongside late Sens. John McCain, R-Ariz., and Joe Lieberman, D-Conn., with whom he traveled extensively overseas. The trio —known as the «Three Amigos» — championed an interventionist Republican foreign policy rooted in American military leadership, support for democratic allies and confronting authoritarian adversaries.

Graham publicly disagreed with Trump over Iran negotiations — preferring strikes and regime change — and repeatedly pushed for a tougher line against Russia in the war on Ukraine.

Those convictions at times put him closer to traditional Republican foreign policy than to Trump’s «America First» instincts, even as he worked to remain one of the president’s closest advisors.

Trump’s approach to foreign policy often shifted between military confrontation and diplomatic restraint. Graham’s rarely did.

Sen. Lindsey Graham is pictured in Kyiv on June 10, one day before his passing. (Valentyn Ogirenko/Reuters)

Whenever Trump appeared to move toward a negotiated settlement with Iran, Graham followed a familiar playbook: remind the White House that Congress ultimately would have to review any lasting agreement.

After Trump announced a memorandum of understanding with Iran in June, Graham quickly argued that any lasting deal would require congressional scrutiny and even suggested Vice President JD Vance would ultimately have to defend it on Capitol Hill.

By the time of his death, Graham had fashioned exactly the role he wanted in Washington: trusted interlocutor between the White House, Congress and foreign leaders.

Sen. Amy Klobuchar, D-Minn., described Graham as having a «kid-like exuberance about his job and the responsibilities he was given.»

«Even in his sixties he would get off a plane in a foreign land with a twinkle in his eye and look at me as if to say, can you believe we are actually here and doing this?» she wrote on X.

Very rarely in life do you get to be exactly where you want to be, when you want to be there, with who you want to be with, doing precisely what you want to do — that was every moment for Lindsey,» White House deputy chief of staff Stephen Miller wrote on X.

«Lindsey was a senator’s senator. The job was everything to him. Truly did he believe in the splendor of the office and the noble lineage behind it, of which he was the worthy heir.»

Graham rarely seemed interested in winning an argument if it meant losing the president. He spent more than a year revising his long-stalled Russia sanctions legislation and negotiating with the White House as Trump pursued his own diplomatic outreach to Russian President Vladimir Putin. Only days before his death did Graham announce that he had reached an agreement with the administration to move the bill forward.

While Trump frequently questioned the value of NATO and demanded allies shoulder more of the burden, Graham viewed America’s alliances as one of its greatest strategic advantages. He generally agreed that European nations needed to spend more on defense, but argued the alliance itself remained indispensable to deterring Russia and projecting American power.

Graham’s support for Israel was equally central to his worldview. He regarded Israel as America’s closest partner in the Middle East and spent years working to strengthen ties between Israel and Arab states, viewing Saudi-Israeli normalization as a historic opportunity to reshape the region while further isolating Iran.

Graham spent a decade proving that in Washington, proximity to power could matter as much as formal authority. Without Graham in Washington, Ukraine now fears it may have lost an indispensable advocate in Washington.

«Huge and absolutely unexpected loss,» said Oleksandr Merezhko, a lawmaker with Zelenskyy’s party, told the AP. «He was truly indispensable. I even don’t know who might be as important for us now in Trump’s entourage.»

«He was the closest link between Ukraine, our president and Trump,» he added. «Our position in Trump’s entourage might be weaker.»

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It’s unclear who will be able to usher Graham’s signature Russia sanctions bill through the Senate and onto the president’s desk with the same access to both ends of Pennsylvania Avenue.

For now, the president will navigate wars in Ukraine and the Middle East without the friend who was never shy about telling him to hit harder.