Before I begin, I should note that there are two major caveats to the polling data that I’m about to share:

The pollster that conducted this poll, HarrisX/Scott Rasmussen (note that HarrisX/Scott Rasmussen is a different pollster than Rasmussen Reports), is a right-leaning pollster: for example, their polling on Donald Trump’s approval rating is consistently more favorable to Trump than the FiveThirtyEight polling average. The poll is a national poll involving hypothetical two-way contests for the Democratic presidential nomination, but there are currently 24 major candidates seeking the Democratic presidential nomination.

Nonetheless, a HarrisX/Scott Rasmussen poll shows Elizabeth Warren narrowly leading hypothetical Democratic primary two-way matchups against Joe Biden and Bernie Sanders, albeit within a typical polling margin of error:

x 2020 National Democratic Primary, Head-To-Head:

Warren 41% (+2)

Biden 39%

.

Warren 40% (+3)

Sanders 37%@Harris_X_/@ScottWRasmussen 5/28-30 — Political Polls (@Politics_Polls) May 30, 2019

For the sake of completeness, Bernie trails Biden, but both Biden and Bernie lead Kamala Harris, in hypothetical two-way matchups. There didn’t appear to be a hypothetical Warren vs. Harris Democratic primary matchup polled, unfortunately. Here’s how the hypothetical head-to-head Democratic primary polling from HarrisX/Scott Rasmussen looks in table form (note that each head-to-head poll is listed twice in the table):

Joe Biden Bernie Sanders Elizabeth Warren Kamala Harris Joe Biden - Biden +2 Warren +2 Biden +3 Bernie Sanders Biden +2 - Warren +3 Sanders +5 Elizabeth Warren Warren +2 Warren +3 - Not Polled Kamala Harris Biden +3 Sanders +5 Not Polled -

It’s worth noting the head-to-head polling shows Biden not far above his polling average within the full Democratic primary field, which is a major warning sign for Biden’s campaign as the Democratic primary field is likely to be winnowed to not more than six or seven candidates once the early primary/caucus states participate in the Democratic nomination process. Furthermore, this is a breakthrough poll for Warren: Warren already leading in hypothetical two-way primary contests, gives Warren, who is running a progressive, policy-focused presidential campaign, an argument that she has a path to the Democratic nomination. I would definitely like to see pollsters with more credibility than HarrisX/Scott Rasmussen poll hypothetical two-way contests, however.