The buzz in Washington is growing: United States President-elect Donald Trump, reports suggest, is about to pick Florida Senator Marco Rubio as his secretary of state.

Rubio, who serves on the Senate Select Committee on Intelligence and the Committee on Foreign Relations and is known for his hawkish approach to US foreign policy, would, if nominated and confirmed by the US Senate, be the first Latino to serve as the country’s top diplomat.

It would also mark a remarkable turnaround from the Republican Party presidential primaries in 2016 when the two men infamously traded churlish nicknames.

Since the public spat, experts said, Rubio appears to have adapted his views over the years on issues such as the war in Ukraine and immigration policies to fall in line with Trump’s stance.

Let’s look at how the Florida senator’s relationship with Trump has changed over time and what we know of Rubio’s views on key foreign policy issues.

How it all began: ‘Little Marco’, ‘Small Hands Trump’

The two men clashed when they came up against each other in the 2016 presidential primaries with Trump mocking Rubio for perspiring profusely and labelling him “Little Marco”.

The remarks prompted Rubio to shoot back: “I don’t understand why his [Trump’s] hands are the size of someone who is 5’2. … And you know what they say about men with small hands? You can’t trust them.”

Yet trust him, he did. After Rubio was knocked out of the primaries, he eventually backed Trump for president.

Do Trump and Rubio agree on Ukraine?

On paper, the two men have different approaches to US foreign policy.

Rubio is more of a traditional interventionist who advocates for a muscular approach to foreign conflicts while Trump’s foreign policy has focused on avoiding military interventions abroad.

This has, at times, moved Rubio to publicly criticise Trump’s foreign policy, including in 2019 when he accused the then-president of “abandoning” the US military effort in Syria before it was “completely finished”.

However, in recent years, experts said, Rubio has softened his stance to fall in line with Trump.

“Rubio is a flexible and pragmatic politician who has accommodated himself to the rise of President Trump,” Paul Musgrave, an associate professor of government at Georgetown University in Qatar, told Al Jazeera.

One such shift is Rubio’s approach to the war in Ukraine.

In the initial months after Russia’s full-scale invasion in February 2022, Rubio took to social media to fervently rally support for Ukraine among Americans.

During that period, he labelled Russian President Vladimir Putin “a killer” and questioned his mental health.

Trump, in contrast, has insisted that Putin would never have invaded Ukraine in 2022 had he been in office.

Trump, who will take office again in January, has also said he could end the conflict “in 24 hours”. He has suggested Ukraine might have to cede territory to Russia to reach a peace deal.

It’s a stance that Rubio appears to have softened to, Musgrave said, but with “a pragmatic, flexible and more appealing face” than Trump’s more verbose rhetoric.

In recent interviews, Rubio has suggested  Ukraine needs to seek “a negotiated settlement” with Russia, and he was one of 15 Republican senators to vote against a military aid package for Ukraine that passed in April.

Rubio has stated that, with Trump in power, the US can expect a more “pragmatic foreign policy”.

Senator Marco Rubio speaks about the conflict in Ukraine and the challenges posed to the United States from China in 2022 [Drew Angerer/Getty Images/AFP]

Are Trump and Rubio aligned in their support for Israel?

The two men initially clashed on the issue in 2016 with Rubio, a longstanding supporter of Israel, accusing Trump of being “anti-Israeli” and publishing a statement titled “Fact Check: Donald Trump Is No Ally to Israel.”

Rubio’s remarks were in connection to Trump suggesting he would “be sort of a neutral guy” in the Palestine-Israel conflict.

In his first term in office, Trump dispelled any question over neutrality after he officially recognised Jerusalem as Israel’s capital.

He has since accused President Joe Biden, who beat him in the 2020 election, of restraining Israel in its war on Gaza and stated during a debate with Biden in June that he will help Israel to “finish the job” if re-elected.

Rubio has had a typically hawkish stance on Israel’s war on Gaza, telling an activist in 2023 that he did not support a ceasefire and Hamas was “100 percent to blame” for the deaths of Palestinians in the Gaza Strip.

He then supported Trump’s plan to deport foreign pro-Palestinian student demonstrators to get them to “behave”.

Nader Hashemi, associate professor of Middle East and Islamic politics at Georgetown University, told Al Jazeera that Rubio’s past comments on the conflict, especially when referencing Palestinians, can at times be “indistinguishable from [Israeli Prime Minister] Benjamin Netanyahu”.

Rubio has previously defended Israel’s right to conduct a ground operation in Rafah despite an emergency ruling by the International Court of Justice for Israel to halt the offensive, citing “immense risk” to the Palestinian population. He compared the Israeli operation to the pursuit of Adolf Hitler during World War II.

But in April, Rubio indicated that he had shifted away from unfettered support for foreign wars – which is more in line with Trump’s approach to foreign policy – when he voted against a package that provided emergency funding to Israel, arguing that the deal should have also included money for US border enforcement.

Rubio speaks at the Temple Beth El to discuss his commitment to stand with Israel in 2016 in West Palm Beach, Florida [Joe Raedle/Getty Images via AFP]

Has Rubio changed his views on immigration to align with Trump’s?

Rubio, the son of Cuban immigrants, appears to have shifted to a more populist approach on immigration.

Musgrave said that earlier in his career, Rubio “was a force for trying to change the Republican Party to be more open to immigration, more open to diversity”.

As a member of the Florida House of Representatives in 2003, Rubio had co-sponsored a version of the DREAM Act, which would have allowed undocumented immigrant students to receive permanent residency if they met certain criteria.

When Rubio became speaker of the Florida House in 2006, he stalled immigration reforms that would have cracked down on undocumented migrants.

After being elected a US senator in 2010, he began to take a tougher stance on immigration, but it remained considerably softer than Trump’s hardline policies towards immigration. For example, in 2016, Rubio stated that mass deportations of millions of undocumented migrants were not “a realistic policy”.

But now, Musgrave said, Rubio has shifted to a more “anti-immigrant, pro-legal immigrant stance that’s in keeping both with his political base and with President Trump’s policies”.

In recent months, however, Rubio has defended some of Trump’s more populist rhetoric, including his comments that immigrants were “poisoning the blood of our country”.

“That’s a saying that he [Trump] uses, but it has nothing to do with race,” Rubio said in a Spanish-language TV interview, adding: “The country is threatened by this influx of people, which we now know even includes criminals and terrorists.”