A liberal firebrand who could stoke the passions of the Democratic base. A Hispanic who could fire up the country's fastest-growing population - and make history. Someone with governing experience who might also help with a key group where Democrats lag: white men.
With less than a week to go before presumed Democratic presidential nominee Hillary Clinton is expected to select a running mate, these are among her choices.
She has focused intensely on the task in recent days, according to multiple interviews with Democrats familiar with her thinking. And she is looking for the best partner in the White House more than the best campaign asset, they said.
So while her highly anticipated announcement could telegraph crucial electoral calculations, it may signal even more how she plans to run the presidency.
The process, which comes to a head this week as Donald Trump and Republicans convene for their national convention in Cleveland, began to come into focus late last week.
A day after campaigning in Northern Virginia with Senator Timothy Kaine, of Virginia, - widely considered a front-runner despite his self-deprecating description of himself as "boring" - Clinton and top aides hunkered down at her Washington home to evaluate a parade of a half-dozen other possible partners.
The takeaway from interviews with dozens of Democrats is that she has an array of options, and her ultimate choice will reveal a great deal about the president she intends to be. Clinton's interviews with the contenders have been short on chit-chat, instead homing in on each candidate's policy chops.
"She has some good choices for whatever it is she feels she needs," said Mo Elleithee, a former Clinton campaign aide who is executive director of the Institute of Politics and Public Service at Georgetown University.
Among those who visited her home on Saturday were Senator Elizabeth Warren, of Massachusetts; Julián Castro, the nation's Housing Secretary; and John Hickenlooper, the Governor of Colorado.
Warren is widely viewed as Clinton's best shot at exciting the party's liberal wing, including supporters of Senator Bernie Sanders of Vermont, the runner-up for the Democratic nomination. But even Warren's advisers are sceptical that Clinton would choose her, given her value in the Senate and the uncertainty of how the two would work together in the West Wing.
Castro and Labor Secretary Thomas Perez, another oft-touted contender, could further engage Latinos in an election where many already feel alienated by Trump's immigration proposals and disparaging comments about Mexicans.
The dark-horse Hickenlooper has submitted financial records and undergone other aspects of the vetting process afforded top contenders, Democrats with knowledge of the process said.
He and two other contenders - Kaine and Tom Vilsack, a former Iowa Governor and current Agriculture Secretary - could help counter Trump's popularity with the white male demographic. Each hails from a battleground state, and all have known Clinton for some time.
Clinton's choice will come at a key moment of her campaign - and is likely to be seen through that lens. She is seeking to consolidate support among liberal Democrats after a bruising primary with Sanders, something she has attempted with overtures on domestic policy and with a spirited campaign appearance with Warren.
With many liberals already viewing her warily, Clinton's vice-presidential selection could make her challenge even greater.
Potentially compounding that threat, Clinton's campaign is also heavily pursuing centrist Republican and independent voters who might not be ready to support Trump.
That might help explain the late addition to her vice-presidential list of James Stavridis, a retired admiral who has no political history but has been friendly with Republicans, including former Defence Secretary Donald Rumsfeld, and who could help shore up Clinton's standing in a race increasingly shaped by terrorism and foreign policy crises.
Indeed, Clinton has made it clear to all her potential picks that national security issues are paramount, a signal that those without them have a higher bar to get the job, according to people familiar with the process.
Clinton's pick could also reveal something about how she wants to be viewed. At every turn, her campaign has sought to contrast her temperament with that of Trump, casting her as a steady hand and him as too erratic for even Republicans to trust with the nuclear codes. With her choice of a running mate, Clinton is almost certain to seek to reinforce that contrast.
There are also external political calculations to consider. Three liberal-leaning senators Clinton has looked at - Warren, Cory Booker of New Jersey and Sherrod Brown of Ohio - would each, at least temporarily, cost Democrats a seat in the chamber just as the party is trying to regain control. That's because Republican governors from their states would appoint their successors. In contrast, Kaine's replacement would be named by Virginia Governor Terry McAuliffe, a staunch Clinton ally.
Some Democrats caution against assigning too much importance to any calculation but one: who Clinton would feel most comfortable governing with. Democrats who know her said she has seen White House operations run well and run badly and is measuring her possible choices with that in mind.
"She's been there," said Joe Trippi, a veteran Democratic operative, citing Clinton's previous roles as first lady and Secretary of State. "She knows what that relationship needs to be. For her, it may literally be a matter of who she wants to work with."
That notion has been a key argument for Kaine, a former Virginia Governor, Mayor of Richmond and chairman of the Democratic National Committee who makes up in competence what he lacks in pizzazz.
A scandal-free former governor from a crucial swing state, Kaine could be a genial antidote for a nominee tarred by decades of controversy. Even Republicans have struggled to find ways to attack Kaine, a Harvard Law School graduate who is fluent in Spanish and who once volunteered as a missionary in Honduras.
In recent weeks, Vilsack has emerged as another leading contender cast from a similar mould. The Iowan has experience as governor of a battleground state and as Agriculture Secretary, which gives him entree to rural America. In his current post, Vilsack has travelled extensively overseas, and he shares Clinton's interest in policy details.
"He's a solid, substantive policy guy, a little on the wonkish side, and sometimes plodding," said Dennis Goldford, a political science professor at Drake University and longtime Vilsack watcher. "He's someone from the dead centre of the party and not an ideological warrior of any sort."
Vilsack also has the longest and possibly closest relationship with Clinton of any of the contenders. She served as a staffer with the late brother of Vilsack's wife on the House Judiciary Committee during Watergate. And Clinton was a strong advocate for Vilsack during his first run for governor in 1998. He repaid Clinton as one of her most loyal supporters in the 2008 Democratic presidential primaries before joining the Obama Administration.
Hickenlooper, whose profile was elevated by his appearance outside Clinton's home on Saturday, has been discreet about the vetting process and was not accompanied by any staff to their meeting. He and Clinton also met three weeks ago in Denver over coffee.
The assets Hickenlooper would bring to the ticket include a background as a successful small-business owner. He also has a quirky authenticity that could help a nominee who has trust issues. And he is a popular governor in another important swing state.
One disadvantage that could work against Hickenlooper is his celebrated aversion to negative campaigning. He is famous for running an ad in which he was fully clothed in a shower, talking about how much he dislikes negative campaigning.
So far, two of Clinton's picks - Kaine and Warren - have received full-dress auditions, appearing alongside the presumptive nominee on the campaign trail.
Kaine joined Clinton last week at a community college in Northern Virginia. He remained mild-mannered and cheery even as he approached attack mode, asking the audience, "Do you want a trash-talk president or a bridge-building president?"
The atmosphere was far more electric last month at a rally in Ohio at which Warren joined Clinton in a blistering tag-team critique of Trump.
"I do just love to see how she gets under Donald Trump's skin," Clinton said. "She exposes him for what he is: temperamentally unfit and totally unqualified."
There probably is no one better positioned than Warren to stir the passions on the progressive wing of the party, where many are disenchanted about a Clinton presidency. And few have demonstrated more ferocity when attacking Trump. But there are several downsides to the selection of Warren, including questions about whether having two women on the ticket would exacerbate Clinton's deficit with male voters.
Over the weekend at Netroots Nation, a gathering a liberal activists in St Louis, there was a sense of resignation that the Democratic ticket probably wouldn't be as progressive as it could be.
"There are a couple choices that would be electric," said Adam Green, co-founder of the Progressive Change Campaign Committee. He ticked off the names of Warren, Brown and Jeff Merkley, a senator from Oregon who backed Sanders but does not appear to be under consideration.
"Then you have people who seem okay once you Google them, like Tom Perez," Green said. "Then there are people who'd deflate all the air out of the balloon. ... That's Tim Kaine. He feels like the kind of brand that Democrats ran in 2014, when they couldn't get anybody to vote."
Bill McMahon, who blogs under the sobriquet DriftGlass, said Warren is better suited to become "the lion of the Senate" than a member of a Clinton administration.
"Knowing Hillary Clinton, she'll want somebody who'll reassure everyone and terrify no one," McMahon said.
Throughout Clinton's search, the prospect of a Hispanic running mate has loomed as a potential masterstroke, given the rapid growth of Latinos nationwide and their deep support for Democrats. Record numbers of Latinos - especially younger people - have registered to vote this year in Arizona, California and Texas and increasingly influence the politics of key swing states, including Colorado, Nevada and Virginia.
Should Clinton want a Hispanic running mate, three names are in the mix: Castro, Perez and Congressman Xavier Becerra of California.
In Becerra and Castro, Clinton has options that may seem most familiar to Americans: They are multi-generational Mexican Americans from California and Texas. Elevating Perez would more deeply contextualise and expand the country's understanding of the Hispanic experience: He's a Dominican American who was born in Buffalo.
Although Perez is not well known nationally, Clinton has become a fan, Democrats say. The Labour Secretary travelled with her last northern winter and impressed her with his energy and passion.
On the downside, Perez's only elective political experience was as a member of the County Council in Montgomery County, Maryland. A lawyer by training, he's more of a policy wonk than a politician. As a Senate staffer, he helped craft healthcare reform legislation, and at the Justice Department under Obama, he defended the Administration's civil rights policies.
Castro has been considered a contender for years, even before he gave a breakout keynote address at the 2012 Democratic National Convention. A former Mayor of San Antonio, he took the Housing Secretary job in 2014 in a move widely regarded as an opportunity to earn national political exposure.
Becerra emerged as another option in the later stages of the Democratic presidential primaries. Having served in Congress since 1993, he is the most senior Latino House legislator, but he is considered a long-shot vice-presidential pick.
There are factors now weighing heavily against selecting a Hispanic. Given Trump's unpopularity and self-inflicted damage with the group, Clinton and her team may not feel the same urgency about courting Hispanic support.