The Democratic presidential contest now has two frontrunners, not just one. Who is ahead depends on which question you ask in the latest Economist/YouGov Poll. Former Vice President Joe Biden and Massachusetts Senator Elizabeth Warren are at the top of the two dozen active candidates.

Warren is more popular than Biden: 72 percent of Democrats have a favorable opinion of her, five times the percentage who are unfavorable. On this item, Biden’s favorability rating is lower – and not much higher than that of Vermont Senator Bernie Sanders, California Senator Kamala Harris, former Texas Representative Beto O’Rourke, and South Bend Mayor Pete Buttigieg. New Jersey Senator Cory Booker is also close to the leaders.

O’Rourke, an El Paso, Texas native, returned to the city after this month’s mass shooting, and espoused a strong pro-gun control position. His actions clearly helped him with Democratic voters. Last week, only 52 percent reported a favorable opinion of O’Rourke. That percentage jumped nine points in this week’s poll. O’Rourke’s unfavorable rating dropped twn points, from 24 percent last week to 14 percent now. Warren’s favorable rating rose from 69 percent last week to 72 percent today.

Warren also is being considered by a few more Democratic primary voters than are currently considering Biden. Last week, the top positions were reversed. Harris and Sanders are in the next group, followed by Buttigieg. But when Democratic voters are asked to name their first choice, Biden and Warren are essentially tied, followed by Sanders and then Harris. No other candidate is named by more than 5 percent of Democratic voters as their first choice.

In the last week, consideration of Warren, Harris, Biden and O’Rourke has increased. Other candidates haven‘t changed much.

Biden is also seen as slightly more electable than Warren among Democratic primary voters: 65 percent believe he would beat President Donald Trump, compared with 59 percent who say the same about Warren.

The rise of Warren has come about through her very strong support from liberals, two-thirds of whom say they are considering supporting her. By contrast, fewer than half of liberals say they are considering Biden and Sanders. Warren has an eight-point lead over both Biden and Sanders when liberals are asked to name their first choice. More than a quarter (27%) choose Warren, while one in five (19%) name Biden and Sanders. Liberals make up more than half of those who say they will be voting in the Democratic primary next year.

Putting a woman at the top of the Democratic ticket could raise long-standing concerns on the question of whether the United States is ready for a female president. More than twice as many Americans say it is than say it isn’t, though many Republicans aren’t sure (47 percent of Republicans say the country is ready, and 42 percent disagree).

Some of the negative GOP responses surely are due to the fact that a woman could win the Democratic nomination and run against Trump, the male incumbent. However, 41 percent of Republicans (35 percent of male Republicans and 46 percent of Republican women) say if they honestly assessed themselves, they would be uncomfortable having a woman as president. Just 9 percent of Democrats say this.

Democrats and Republicans take different positions on whether or not it is important to them that a woman be elected President in their lifetimes. Most Democrats say it is extremely important (31%) or very important (26%) that this happens. Half of Republicans (49%) say it’s not important at all.

At the moment, female presidential candidates – present and future – are more visible in the Democratic Party. But Republicans aren’t even sure about electing a Republican woman to the White House. Just a third of Republicans say it would be a good thing for the country if that happened, and a quarter say it would be a bad thing. The rest aren’t sure.

By contrast, 84 percent of Democrats believe electing a Democratic woman as president would be a good thing for the country, and even a quarter agree that electing a Republican woman would also be good for the country.

See the full toplines and tables results from this week's Economist/YouGov poll.

Related: Is gun control legislation even possible in America?

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