WASHINGTON – Sens. Bernie Sanders and Elizabeth Warren have jumped to a virtual tie with front-runner Joe Biden in a new poll on the Democratic presidential candidates.

Sanders and Warren are both tied at 20%, with Biden at 19%, according to a Monmouth University national poll published Monday.

Biden, the consistent leader in polling throughout the primary election cycle, dropped 13 percentage points from June, where he was at 32%. That gap appears to be shrinking.

Both Sanders and Warren saw a small jump from June, by 6 percentage points and 5 percentage points respectively. Those are the only three candidates to hold double digits in that poll.

The poll carves out the leading candidates in a sprawling 2020 field. Over the last several weeks, however, a number of Democratic candidates have dropped out. Most recently, Rep. Seth Moulton of Massachusetts announced he was ending his bid.

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The next candidate behind the leading three was Sen. Kamala Harris at 8%. Sen. Cory Booker and Mayor Pete Buttigieg polled at 4%; entrepreneur Andrew Yang was at 3%; and Texans Julián Castro and Beto O'Rourke, along with Marianne Williamson, were all at 2%.

This poll counts towards the next Democratic primary debate in September, where candidates are required to have at least 2% support in four polls and contributions from at least 130,000 individual donors.

Among Democratic support in early states, Warren and Biden are out 20%. Biden fell 6 percentage points from June while Warren spiked 5 percentage points. Sanders followed at 16%.

However, among Democrats in other states, Sanders leads at 23% — a 10 percentage point jump from June. Warren was also at 20% among Democratic support in other states. Biden was at 17% in Democratic support from other states, a 21 percentage point drop from June.

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In addition, Warren's favorability ratings are also rising. She is at 65% favorable and 13% unfavorable. In May, she was at 60% favorable and 14% unfavorable.

Biden, on the other hand, has also fallen in favorability. He is 66% favorable and 25% unfavorable, while in May he was at 74% favorable and 17% unfavorable. Biden, who paints himself as a more centrist Democratic candidate, throughout the campaign has touted his electability.

Patrick Murray, director of the independent Monmouth University Polling Institute, said in a statement that more progressive voters are now starting to "cast about for a candidate they can identify with," while more moderate voters are beginning to express doubt about Biden.

“The main takeaway from this poll is that the Democratic race has become volatile," he said, adding: “It’s important to keep in mind this is just one snapshot from one poll. But it does raise warning signs of increased churning in the Democratic nomination contest now that voters are starting to pay closer attention.”

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