President-elect Donald Trump announced Florida Sen. Marco Rubio as his choice for his next secretary of state on Tuesday, selecting a loyalist who has advocated for U.S. intervention abroad and who is not favored among Trump’s more isolationist-leaning supporters and allies.

Rubio, a 53-year-old in his third Senate term, was one of Trump’s more critical opponents during the 2016 Republican presidential primary but has since fully embraced his party’s leader and become one of his most consistent supporters in and out of office. 

The son of Cuban immigrants and a veteran of Miami Republican politics, Rubio has long backed an aggressive U.S. foreign policy stance, expressing support for Israel’s continued bombardment of the Gaza Strip and neighboring countries, an increasingly adversarial U.S. stance toward China and regime changes in Venezuela, Cuba and Iran.

He is also an avowed supporter of NATO, the military alliance with European allies that Trump has long been critical of, but he has strayed from his early support for Ukraine in its war against Russian invaders. In April, Rubio voted against a $95 billion aid package for Ukraine. He has also begun to argue for “a negotiated settlement” to the end of the war as Trump has left the door open to supporting a deal in which the country would give up some territory seized by Russia, a nonstarter for Ukrainian President Volodmyr Zelenskyy. 

“It is my Great Honor to announce that Senator Marco Rubio, of Florida, is hereby nominated to be The United States Secretary of State. Marco is a Highly Respected Leader, and a very powerful Voice for Freedom,” Trump said in a statement Wednesday. “He will be a strong Advocate for our Nation, a true friend to our Allies, and a fearless Warrior who will never back down to our adversaries. I look forward to working with Marco to Make America, and the World, Safe and Great Again!”

Rubio thanked the president-elect in a statement, writing that he was “honored” and “will work every day to carry out his foreign policy agenda.”

“Under the leadership of President Trump, we will deliver peace through strength and always put the interests of Americans and America above all else,” Rubio said, adding he hoped the Senate would confirm him swiftly so Trump “has his national security and foreign policy team in place” by the time he takes office on Jan. 20, 2025.

The Florida Republican held outsized influence during Trump’s first term on the then-president’s Latin America policy and has been the top Republican on the Senate’s Select Committee on Intelligence since 2020. In a different era, Rubio was a member of the bipartisan “Gang of Eight” during the Obama administration, when he and seven other top senators split evenly among the parties attempted to find a path forward on comprehensive immigration reform.

More recently, Rubio has been one of Trump’s biggest boosters as he marched back to securing the White House, making the case that the president-elect will undo much of President Joe Biden’s foreign policy “weakness.” He was reportedly considered as a possible running mate before Trump chose Ohio Sen. JD Vance.

“The world is in total chaos, and you can link it all the way back to the day that we were run out of Afghanistan by the Taliban, humiliated in the way that we were,” Rubio told Fox News in late October. “That was a signal to the world, not just that Joe Biden and Kamala Harris are weak, but that America is weak and now is the time to act.”

“It’s not a coincidence that since that moment we have had the invasion in Ukraine, we have had Oct. 7, we have had all the things happening now in the Middle East. We have the Houthis endangering global shipping in the Red Sea. We have the Chinese harassing the Philippines and making plans to invade Taiwan. None of these things are coincidental,” Rubio continued.

Trump has both pledged to wield the military against U.S. citizens, immigrants and Mexican drug cartels, while also promising to end the war in Ukraine and conflicts in the Middle East. He frequently framed his reelection as Americans' only chance to avoid “World War III.” Rubio will be tasked with leading the diplomatic effort to make those pledges a reality. 

“We would have had peace in the Middle East,” Trump said at a campaign rally in Reading, Pa. “You would have had peace. Instead, you have all of the death that's taking place. It's terrible. And I will prevent World War III because you're just around the corner from World War III. And this will be a war like no other. This will be a nuclear war.”

Despite his loyalty to Trump, Rubio’s foreign policy stances are at times at odds with Trump, who pledged to end foreign conflicts and keep the United States out of future wars. Long associated with neoconservative thought, Rubio represents a direct contrast with the rhetoric and politics of key Trump allies such as billionaire Elon Musk, former Fox News host Tucker Carlson and even Vance, all of whom have pushed the party to embrace more “America First” isolationist postures.

Robert F. Kennedy Jr., the former independent presidential candidate and anti-vaccine proponent who will be involved in health policy in Trump’s administration, opposed the pick, according to The Hill. Far-right activist Charlie Kirk, an influential figure in Trump’s world, and Florida Rep. Anna Paulina Luna both urged the president-elect’s online supporters opposed to Rubio to be patient after the news was reported but before Trump officially announced it.

Another Florida Republican, Rep. María Elvira Salazar, praised Rubio’s selection, writing on social media “it’s a bad day to be a dictator in Latin America.” And fellow Florida Sen. Rick Scott, who sought unsuccessfully to be the Senate GOP’s next leader, congratulated Rubio on Monday night before the pick was official. 

On Sunday morning, the president-elect’s eldest son, Donald Trump Jr., a key campaign surrogate and adviser to his father who had opposed Rubio being the vice presidential nominee, wrote on social media that he “agreed” with the sentiment from far-right influencer Dave Smith that “we need maximum pressure to keep all neocons and war hawks out of the Trump administration.” That conversation came in response to Trump announcing he would not be welcoming his former secretary of state, Mike Pompeo, and former U.N. Ambassador Nikki Haley back into his next administration. Trump announced Monday he was nominating New York Rep. Elise Stefanik, one of his most loyal congressional supporters and an avowed defender of Israel’s war efforts, to be the U.S. ambassador to the United Nations.

But where Rubio loses Trump support among some of his base, he could insulate his administration from concerns in foreign capitals, centrist Democrats and the hawkish members of his own party. Like all Cabinet-level positions, secretaries of state are required to be confirmed by the Senate, with Rubio likely to cruise through that process as a long-standing member of the chamber, which will be controlled by Republicans at the start of Trump’s administration. 

Pennsylvania Sen. John Fetterman, a Democrat whose own hawkish foreign policy has lost him his status as a darling of the progressive movement, has already said he will vote for Trump’s “strong choice” in Rubio. Trump critic and Harris campaign surrogate Adam Kinzinger, a former Republican House member from Illinois, also cautiously praised the pick.

If Rubio is successfully nominated, Florida Gov. Ron DeSantis would be tasked with appointing a replacement who would then serve through a 2026 special election to fulfill the rest of Rubio’s term, which ends in 2028. While some reports indicate DeSantis may pick his chief of staff,  James Uthmeier, or another ally, some Trump allies are already calling for his daughter-in-law Lara Trump, co-chair of the Republican National Committee, to be appointed.

"She understands the America First agenda,” Alabama Sen. Katie Britt told Axios on Tuesday. “For me, I think she would be a tremendous pick, a voice for hard working families and another mom of school aged kids that understands what we're up against, and that's to fight to protect the American dream. 

Luna, the Florida representative, also publicly urged DeSantis to pick Lara Trump, arguing “she will keep the seat and avoid a messy primary” in 2026 and 2028. Musk praised the president-elect’s daughter-in-law, writing she’s “genuinely great.”

If confirmed, Rubio would replace current Secretary of State Antony Blinken, a career foreign policy official and longtime Biden aide who is the only person to serve in the role for the last four years. 

Fresh off an election in which growing support among the Latino community helped deliver Trump the White House, Rubio will be the first Latino to ever serve as the United States’ top diplomat. Trump, who has called for the rounding up and deportation of millions of Latino undocumented immigrants, only had one Latino official in his Cabinet the first time around: Labor Secretary Alexander Acosta, who served from 2017 to 2019. 

As is the case with many in Trump’s orbit, including Vance, Rubio has not always been a fan of his new boss. The two fiercely feuded on the campaign trail in 2016, mocking each other with schoolyard taunts about the size of the other’s genitals. Trump derogatorily dubbed him “Little Marco” and ruthlessly mocked him on social media and in speeches. Eventually, Rubio endorsed his party’s candidate and worked to earn the then-president’s trust during his first term. Unlike many still in Trump’s orbit, Rubio did vote to certify the Electoral College count for the 2020 election on Jan. 6, 2021, and had referred to Biden as president-elect as early as November 2020 amid efforts by Trump to spread doubt about the election’s integrity in a bid to stay in power. 

Still, Rubio voted against creating a commission to investigate the Jan. 6 attack on the U.S. Capitol and voted to acquit Trump during his second impeachment trial centered on that attack by his supporters.

Before he joined forces with Trump, Rubio had a warning for Republicans who hitched their wagon to the candidate he described as “a third world strong man.” In March 2016, just before he dropped out of the race, Rubio went on CNN to discuss a recent spate of violent incidents at Trump campaign rallies, which the Florida senator blamed on the New York businessman and said made him “very concerned” someone might die.

“I can tell you this: No matter what happens in this election, for years to come, there are many people on the right, in the media and voters at large that are going to be having to explain and justify how they fell into this trap of supporting Donald Trump,” Rubio said. “Because this is not going to end well one way or the other.”