The latest national polls indicate former Vice President Joe Biden and Sen. Elizabeth Warren of Massachusetts trading the lead for the 2020 Democratic presidential nomination with the first caucuses and balloting still more than 18 weeks away.

The next Democratic debate is set for November and will be limited to candidates polling at least 3% in four polls or 5% in two state polls from Iowa, New Hampshire, South Carolina and/or Nevada. They’ll also need at least 165,000 unique donors and a minimum of 600 unique donors in 20 states.

The Real Clear Politics average of polls indicates Biden has 29% support compared to 21.4% support to Warren. They’re followed by Sen. Bernie Sanders of Vermont with 17.3%, South Bend (Ind.) Mayor Pete Buttigieg with 5.8%, Sen. Kamala Harris of California with 5% and entrepreneur Andrew Yang with 3.3%.

Former Rep. Beto O’Rourke of Texas, Sens. Cory Booker of New Jersey and Amy Klobuchar of Minnesota, former Housing Secretary Julian Castro and Rep. Tulsi Gabbard of Hawaii all are polling less than 3%.

The Quinnipiac University poll released Wednesday put Warren and Biden running first and second in a dead heat, separated by just 2 points, with Warren having made up a 13-point deficit from August’s tally. Warren’s greatest gains were among white voters with college degrees. The same poll indicates only a third of Americans (37%) think President Trump should be impeached.

The September Emerson poll released Monday put Yang in fourth place with 8%, behind Biden with 25%, Warren with 23% and Sanders with 22%. And though Biden polled 25% support, 22% of those queried said they’d be disappointed if Biden were the nominee.

“This is exactly the news we needed heading into the final days before our end-of-quarter fundraising deadline,” the Yang campaign said in an email.

Biden appears to have a double-digit lead in South Carolina, where primary voters will cast ballots Feb. 29, but support in Iowa and New Hampshire, may be softening.

The Iowa Poll released Sunday gives Warren a 2-point lead over Biden at 22% ahead of the Feb. 3 caucuses. Her support surged from just 8% in December.

In New Hampshire, which votes Feb. 11, FiveThirtyEight reports Warren has an 11-point lead over Biden and 25-point lead over Sanders in a three-way race. When other candidates are added in, Warren still polls 3 to 5 points better. A Monmouth University poll indicates Warren ahead of Biden 27% to 25%, followed by Sanders and Buttigieg. A February poll had pegged Warren’s support at 8%.

“Warren continues to look stronger with every new poll. She seems to be picking up support across the spectrum with gains coming at the expense of both Biden and Sanders,” said Patrick Murray, director of the Monmouth University Polling Institute.

Nevada, where Biden holds a 4-point lead over Warren, holds its caucuses Feb. 22.