(Reuters) -Republican presidential candidate Donald Trump's search for a running mate to help take on Democratic President Joe Biden in November is narrowing to a shortlist.

Trump has said he is likely to reveal the pick for his No. 2 at the Republican National Convention in July, when he will also be formally nominated as the party's presidential candidate.

The top contenders include U.S. senators, governors and other Trump allies. They are almost all men. Sources say the deliberations are fluid, and the former president could still choose someone who isn't on most people's radar.

Here is a look at some potential Trump running mates:


The Miami-born Rubio, 53, has emerged as a leading contender for the vice presidential nod, sources familiar with the matter said. Rubio, a longtime U.S. senator from Florida and son of Cuban immigrants, ran unsuccessfully in 2016 for the Republican presidential nomination eventually won by Trump. Rubio endorsed Trump for the 2024 nomination in January. Aides to Trump say Rubio could help the former president peel away Hispanic voters from Biden in battleground states. As the top Republican on the Senate Intelligence Committee, Rubio would also bring foreign policy chops. The U.S. Constitution poses a problem, however, since it bans the electors who formally select the president and vice president from voting for both from their home state - and both Trump and Rubio call Florida home.


Vance, 39, who is serving his first term as a U.S. senator for Ohio, is another top contender for Trump's running mate, according to sources. It is quite a U-turn for Vance, who rose to fame in 2016 with his memoir "Hillbilly Elegy" about growing up poor in Appalachia. That year Vance was a fierce critic of Trump, at one point calling him "cultural heroin." Since 2018, however, Vance has embraced Trump, who endorsed him when he ran for Senate in 2022. Vance is seen as young, smart and a skilled defender of Trump.


Burgum, a multi-millionaire former software executive who now serves as North Dakota's governor, has risen up the list of possible Trump running mates. Burgum gained some national name recognition when he announced his own presidential bid as a Trump rival in 2023. Burgum's White House run was relatively short-lived and after dropping out of the primary race he was quick to endorse Trump and become a loyal defender. Trump likes the 67-year-old Burgum's background as a successful business executive and views him as a safe pair of hands, people familiar with Trump's thinking said. Burgum is still a relative unknown, however, and he does not bring any geographical help to the ticket, as North Dakota is a safe Republican state.


Scott, a U.S. senator from South Carolina who is Black, has become a fiercely loyal Trump ally since he ended his own presidential bid in November. Aides have been urging Trump to pick a woman or a Black man to add diversity to the ticket and attract more moderate voters. Trump has publicly praised the 58-year-old lawmaker, calling him a "great advocate." It remains to be seen whether the mild-mannered Scott would be well-suited for the traditional "attack dog" role of a running mate. Scott is also a formidable fundraiser, and money is something Trump will need to take on Biden's campaign war chest, as well as to pay his mounting legal bills.


Noem, serving her second four-year term as South Dakota's governor after a landslide reelection victory in 2022, is close to Trump. She rose to national prominence after refusing to impose a statewide mask mandate during the COVID-19 pandemic. Noem, 52, campaigned for Trump at several events in neighboring Iowa in January. "I think anybody in this country, if they were offered it, needs to consider it," she said when asked by CBS in January about being Trump's running mate. But Noem has had a turbulent few months politically and has been sliding out of contention. In March, she became the target of a lawsuit and a request by a Democratic state legislator for an inquiry after she posted an infomercial-style plug for a cosmetic dental practice in Texas where she had work done. She faced widespread backlash in April when she wrote in a memoir that she shot to death an "untrainable" dog that she "hated" on her family farm.


Stefanik, a U.S. representative from New York, is another fiercely loyal Trump ally and a rising star in the Republican Party as the House's highest-ranking woman. She gained national prominence in December after embarrassing the heads of three top universities about antisemitism on their campuses during a congressional hearing. Two of them later resigned, including the president of Stefanik's alma mater, Harvard University. Stefanik was one of the 147 members of Congress who voted not to certify Biden's 2020 election win on Jan. 6, 2021, the day Trump supporters rioted at the U.S. Capitol. There are concerns among some Republicans that Stefanik, 39, may be too inexperienced for the presidential ticket.


The second-term U.S. senator from Arkansas has unexpectedly emerged as a contender for Trump's running mate in recent weeks. Cotton, 47, is a U.S. Army veteran who served in Iraq and Afghanistan, and a Harvard-educated attorney. A Trump loyalist, Cotton is a frequent guest on cable news shows, something Trump likes. He may reflect Trump's desire to have a steady operator on the presidential ticket who will not stir up controversy.


Donalds, 45, is a Black U.S. representative from Florida. A conservative who belonged to the far-right Tea Party movement, he voted not to certify Biden's 2020 election win on Jan. 6, 2021. After Trump told Fox News in February that Donalds was on his short list, Donalds told Reuters the prospect was "pretty cool" and confirmed he wanted to be Trump's running mate. Donalds in June was forced to defend controversial remarks when he appeared to express nostalgia for the Jim Crow era, named after a series of U.S. laws that defined the height of racial segregation. Democrats called his comments outrageous and ignorant; Donalds said his comments were taken out of context.


Carson is Trump's former housing and urban development secretary. A retired neurosurgeon, Carson, 72, unsuccessfully ran for the Republican presidential nomination in 2016. He rose to national prominence as a Black conservative after a 2013 speech at the National Prayer Breakfast when he criticized the policies of Barack Obama, with the then-Democratic president sitting just feet away. Carson, a Seventh-day Adventist, stumped for the Trump campaign this election cycle by visiting churches in Iowa. However, his low-key, quirky campaign style could knock him off the VP list.


Sanders, 41, the Arkansas governor, is Trump's former White House press secretary. She frequently defends his record from the governor's mansion in Little Rock. A seasoned, battle-tested spokesperson, she would be a skilled advocate for the former president on the campaign trail. It is unclear whether she would take the job of running mate. "I absolutely love the job I have," she said in January. Sanders' father, onetime presidential candidate and former Arkansas Governor Mike Huckabee, has also been a longtime supporter of Trump.


A former Democratic congresswoman who ran for president as a Democrat in 2020, Gabbard left the party in 2022 to become an independent. She has become increasingly critical of Biden and his administration, and she has become hugely popular among conservatives and a frequent guest on far-right TV and radio shows. In February, Gabbard, 43, was a headline speaker at CPAC, the Conservative Political Action Conference, where she accused Trump's Democratic critics of having the "mentality of dictators." The fact she was a longtime Democrat may work against her in securing the No. 2 spot.


Some Republicans believe Haley, the former U.N. ambassador who was Trump's last remaining rival for the Republican nomination, would be an ideal running mate. She appeals to the more moderate Republican and independent voters Trump needs to help him beat Biden. Haley, 52, has insisted she will not be Trump's running mate, and she angered Trump by taking so long to quit the nominating race. However, in a possible sign of rapprochement, Haley last month announced she will vote for Trump, calling Biden a "catastrophe."

(Reporting by Tim Reid; Additional reporting by Steve Holland, Gram Slattery and Alexandra Ulmer; Editing by Colleen Jenkins, Jonathan Oatis, Christian Schmollinger and Daniel Wallis )

By Tim Reid