(NewsNation) — As the Republican National Convention approaches, Sen. Marco Rubio, R-Fla., is rumored to be rising in the race to become former President Donald Trump’s running mate.

Trump, the presumptive nominee, has toyed with expectations as he weighs candidates to join him on the ballot. While Rubio once had a combative history with Trump, he’s now said to be rising to the top of that list.

Now a staunch ally of the former president, could Rubio be joining the bid for the White House?

Marco Rubio’s path to Congress

Born to Cuban immigrants in Florida, Rubio entered public service through local government after he graduated from law school. When serving in Florida’s legislature, Rubio became the first Cuban-American to act as the speaker of the House in the state.

Rubio clashed with centrist Republicans in Florida’s Senate and Florida Gov. Charlie Crist during his time in office. Though Rubio tried to push Florida to the right, he was also known behind the scenes as someone who would work across the aisle and supported a proposal for the state government to apologize for slavery while also backing initiatives focused on helping Black youth.

After being elected to the U.S. Senate in 2011, Rubio attempted a run for the presidency in 2016, suspending his campaign as Trump moved to gain the party’s nomination.

In the Senate, Rubio worked across the aisle on some issues, including immigration reform as part of the bipartisan Gang of Eight. The group proposed a comprehensive immigration reform plan that would have included a pathway to citizenship for people currently in the U.S. who had crossed into the country illegally. The plan was never taken up by the House.

Rubio’s positions

Rubio is considered one of the most conservative senators in Congress, despite his position on immigration reform having diverged from the party’s consensus at one point. In the years since that proposal, he has moved toward a more hard-line view on immigration, including his response to the current border crisis.

He rejects the scientific consensus on climate change, opposed the Affordable Care Act and objected to efforts to reduce harsh sentences for drug-related crimes. Rubio is an abortion opponent, supporting a full ban on the procedure with the only exception being if the mother’s life is at risk.

Rubio has supported closing the federal Department of Education, been a strong proponent of charter schools and opposed gun control efforts even in the wake of the 2018 shooting at Stoneman Douglas High School in Parkland, Florida.

The senator has supported a cap on economic regulations and advocated for an increase in the retirement age for Social Security.

In terms of foreign policy, Rubio supported U.S. interventions in Iraq and Libya and has been supportive of sanctions against Iran. He has warned against China’s influence in the global sphere, supporting higher tariffs to limit the country’s ability to export cheaper products to the U.S.

Rubio has been a strong supporter of Israel in the wake of October 7, but also voted against a foreign aid bill that provided funding for Israel, Ukraine and Taiwan. In his rejection of the bill, he pointed to the economic struggles faced by Americans compared to the billions of proposed foreign aid.

Rubio and Trump’s relationship

While competing for the 2016 GOP nomination, Rubio and Trump butted heads. Rubio referred to Trump as a “con man,” mocking the former president’s spelling errors on social media and referring to his outbursts as meltdowns.

Trump, in return, christened Rubio “Little Marco” and attacked his appearance, including mocking him for having large ears and accusing him of sweating too much.

After Trump was elected, however, Rubio became a staunch supporter of the former president. Rubio also shifted his views to more MAGA-friendly positions, including taking a harsher stance on immigration, moving from his usual interventionist foreign policy view to side with isolationists against aid for Ukraine and opposing a Congressional investigation into the Jan 6. riot.

While Rubio voted to certify the results of the 2020 election at the time, he has recently refused to publicly commit to accepting the 2024 results, accusing Democrats of sowing doubt about the electoral process.

What would Rubio bring to the ticket?

Trump and President Joe Biden are vying for key voting blocks including young voters and voters of color. At 53, Rubio is relatively youthful compared to both candidates, whose ages have been a concern with voters. His Cuban-American background could also help woo Latino voters who have played an increasingly important role in elections.

Although he has shifted to the right in recent years, Rubio’s history of working across the aisle and his significant foreign policy experience could appeal to centrist voters Trump will need to win over in the general election.

One challenge is Rubio’s Florida residency because the 12th Amendment prevents both a president and vice president from being from the same state. Rubio has suggested a willingness to take advantage of a loophole, however, and change his official residency to appear on the ticket.