(CNN) Former Vice President Joe Biden's primary campaign is set to embody a massive debate inside the Democratic Party: Is it more important to have a nominee steeped in progressive policy or one the party thinks can beat President Donald Trump, regardless of the accuracy of that assessment?

A new poll out this week shows Biden, still in the earliest days of his campaign, gets high marks from Democrats on his potential ability to beat the President in November 2020. But his policy positions are not nearly as popular with voters as he is, a problem some other big-name Democratic candidates don't face.

No other candidate even came close Biden's number when voters were asked if they thought each individual candidate could win against Trump. The next best were Sen. Bernie Sanders (12%) and South Bend, Indiana, Mayor Pete Buttigieg (4%).

Biden has a clear advantage in this category -- not just because he is up by so much more in this category than anyone else, but because it's an increase from the overall people who say they plan to vote for him. Almost four-in-ten (38%) Democrats and Democratic-leaning independent voters said they'll support Biden in the primary from the new poll.

That means the percentage of voters who think Biden can beat Trump is 18 points larger than the percentage of voters who would vote for the former vice president in the Democratic primary if it was held today. That shows Biden has a built-in positive perception, even outside of his main voting base.

In comparison, other candidates are at a disadvantage in this area. Twelve percent of Democrats and leaning voters said they'll support Sen. Elizabeth Warren in the primary race, but only 3% said she has the best chance of beating Trump -- a difference of 9 percentage points. Mayor Pete Buttigieg and Sen. Kamala Harris face a similar disadvantage in this category, with 6 percentage points less for each who said they'll vote for them versus think they're the best candidate to beat Trump.

Biden also maintains a strong advantage on the question of leadership. When asked who they think is the best leader, 44% of Democrats and Democratic-leaning independent voters chose the former vice president, a six percentage point advantage over the number who said they'll vote for him. He's followed by Warren and Sanders -- both with 11% who said they're the best leader, no real change from the number who plan to support them.

But, where Biden is lacking comes in voters' views on his policy positions.

While 38% say they vote for him in in the primary if it was held today, only 23% said he has the best policy ideas. He still has the plurality of the group, but the difference on the issue is 15 percentage points, a substantial decrease.

Meanwhile, both Warren and Sanders have a significant increase when it comes to policy -- Warren up seven percentage points and Sanders up five.

Warren has often been lauded for her progressive policy proposals in this election, despite her poll numbers placing her squarely in the middle of the large Democratic field. She's based her campaign on her positions and proposals for things like college debt forgiveness, health care and taxing the wealthy, among others.

It's unclear if voters' less positive view of Biden's policy positions will hurt him in the long run. Biden, only a week in to his declared candidacy, has yet to unveil any major policies for his run, but is known for his past moderate voting record.

When asked if they had to choose, 54% of Democrats and Democratic-leaning independent voters said it's more important to have a candidate who would be a great leader than a candidate who has great policy ideas (42%).

And, in a recent CNN poll conducted by SSRS, 92% of Democrats and Democratic-leaning independent registered voters rated having a good chance of beating Trump as extremely or very important in deciding who to vote for, the highest rated issue for importance of the ones tested. Two-thirds said holding progressive positions on issues was extremely or very important.

In a head-to-head general election matchup in CNN's poll, Biden edged out Trump, 51% to 45% among registered voters, with no significant difference in his lead over Trump compared to some other Democrats tested. This early on, he has no more of an advantage over Trump than most of his Democratic opponents.

Of course, it's still early days in the race, and while some Democrats hold a meaningful edge on head-to-head matchups with the President, the results suggest a close race between Trump and most of the Democratic candidates.

There is a lot of time for voters to change their minds. In CNN's first test of a general election matchup between Trump and Hillary Clinton in June 2015, Clinton led Trump by 14 points among registered voters.

The Quinnipiac University poll was conducted April 26 through 29 among a random national sample of 1,044 voters with a margin of error of +/- 3.5 percentage points, including the design effect. Voters were reached on landlines or cellphones by a live interviewer.

The CNN Poll was conducted by SSRS April 25 through April 28 among a random national sample of 1,007 adults reached on landlines or cellphones by a live interviewer. Results for the full sample have a margin of sampling error of plus or minus 3.8 percentage points. Random half-samples can result in smaller subgroup sizes that fall below our minimum for publishing crosstabs for those groups.