Presumptive Republican nominee Donald Trump knows what he wants in a running mate.
The billionaire has insisted that he would pick someone with legislative experience in order to complement his own skill set, which is skewed towards business. In an interview with MSNBC, he said his pick would be "somebody that can help me get things passed and somebody that's been friends with the senators and congressmen".
So someone like Alabama Senator Jeff Sessions might be in the running, said experts. "He and Trump appear to get along. Sessions has strong conservative credentials, he also has some national defence experience," said political science professor Jeffrey Hill from Northeastern Illinois University.
While experts agree that Mr Trump needs someone with political experience to balance the ticket, too many ties with Washington could also be a disadvantage.
Dr Kelly Winfrey, from Iowa State University's Carrie Chapman Catt Centre for Women and Politics, said: "He has to be careful not to pick someone that is too much a part of the establishment because his 'outsider' status is one of the most appealing attributes for his supporters."
She added that picking a governor might work as he or she would have executive experience in a state, but still be regarded as a Washington outsider.
Some names that fit the bill include former presidential hopeful and New Jersey governor Chris Christie, who was quick to endorse Mr Trump after suspending his campaign, and Oklahoma governor Mary Fallin, who has said she is "behind Donald Trump 100 per cent".
While some have speculated that Mr Trump might pick a woman to boost his favourability among women - according to Gallup seven in 10 women have an unfavourable view of him - co-authors of the book The VP Advantage, Dr Christopher Devine and Dr Kyle Kopko, said their research shows that picking a woman as a running mate would not help Mr Trump, or any other candidate, win more votes from women.
Dr Devine, assistant professor of political science at Mount Vernon Nazarene University, said the past two female vice-presidential candidates, Ms Geraldine Ferraro in 1984 and Ms Sarah Palin in 2008, did not win more female voters to their ticket; voters make their decisions based on the characteristics of the presidential candidate, not the running mate.
However, Dr Kopko, who is assistant professor of political science at Elizabethtown College, points out that Mr Trump's campaign might still choose a woman as "the running mate plays an important role of an attack dog when one campaign wants to wage criticism on the other party without the presidential candidate getting involved".
"A female running mate could criticise Hillary (Clinton) more effectively than a man," he said.
As for choosing a running mate from a key swing state, the traditional political wisdom is that this might help a ticket win that home state. But the two authors say their research does not support this, and someone like Ohio governor John Kasich would not help Mr Trump.
"According to our research, candidates from such large states do not deliver a home state advantage," said Dr Devine. "If Trump is looking for a home state advantage, he would be wiser to look toward a competitive and relatively less populous state such as New Mexico, Nevada, Iowa or New Hampshire."
Two possible names are Governor Susana Martinez of New Mexico and Senator Joni Ernst of Iowa, said Dr Devine.
The other problem that might crop up for Mr Trump as he reaches out to possible running mates is the willingness of the other party to join his team.
"The party is not thrilled by the Trump candidacy and I think most Republicans that still have a long career ahead of them will stay away from Trump." said Dr Winfrey.
"I don't know if there is a sitting Republican governor in any swing state that would be willing to be on the ticket with Trump."
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