Sen. Bernie Sanders, former Vice President Joe Biden, Sen. Elizabeth Warren and South Bend Mayor Pete Buttigieg at the Oct. 15 Democratic Presidential Debate at Otterbein University in Westerville, Ohio. Photo: Chip Somodevilla/Getty Images

A clear top tier is emerging in the 2020 Democratic race — but the likely eventual nominee is far from certain, an ABC News/Washington Post poll published early Sunday shows.

Why it matters: Per the Washington Post, the race is "competitive and fluid less than 100 days before the Iowa caucuses, with a stable trio of leading candidates" — the frontrunner, former Vice President Joe Biden (27%); Sen. Elizabeth Warren (21% ); Sen. Bernie Sanders (19%); and fourth-placed South Bend Mayor Pete Buttigieg (9%) breaking away from other single-digit rivals.

  • About half of Democrats polled who support a candidate say they’d consider another one.

Worth noting: Sanders’ health is a concern for a large portion of the of 1,003 Democrats surveyed in the poll several weeks after he had a heart attack. He's vowed to run a "vigorous campaign.

  • "The poll notes that "younger adults, who are among Sanders’ strongest supporters, are most apt to think he’s in good enough health to serve — six in 10 18- to 39-year-olds say so. Just 40 percent of those age 40 and older agree."

Read the full poll:

Go deeper: The problem with 2020 presidential polls

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Hurricane Zeta makes landfall on Louisiana coast as Category 2 storm

A satellite image of Hurricane Zeta. Photo: National Hurricane Center/NOAA

Hurricane Zeta is "battering southeastern Louisiana and southern Mississippi with life-threatening storm surge, high winds, and heavy rain," per the National Hurricane Center.

What's happening: The hurricane was producing maximum sustained winds of nearly 110 mph and stronger gusts after making landfall on the southeastern coast of Louisiana as a Category 2 storm earlier Wednesday.

Supreme Court rejects GOP push to cut absentee ballot deadline in N.C.

Photo: Robert Alexander/Getty Images

The Supreme Court on Wednesday rejected a request by Republicans to shorten North Carolina's deadline for mail-in ballots from nine to three days.

The big picture: This is the latest of a series of decisions over mail-in ballot deadlines in various states.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Politics: Biden ahead in Wisconsin, Michigan as cases surge in the Midwest.
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  3. Business: Surge is sinking consumer confidence Testing is a windfall.
  4. World: Europe faces "stronger and deadlier" coronavirus wave France imposes lockdown as Macron warns of overwhelming second COVID wave Germany to close bars and restaurants for a month.
  5. Sports: Boston Marathon delayed as COVID-19 surges MLB to investigate Dodgers player who joined celebration after positive COVID test.