The survey of 701 likely caucus attendees was conducted January 2-8 and has a margin of error of 3.7 percentage points.
"No candidate will win the Democratic presidential nomination without significant support from African Americans", wrote Post columnist Jonathan Capehart in his analysis of the poll.
While the poll offers no front-runner, it does provide additional insight to where voters are shifting, with good news for Sanders and warning signs for Biden.
In the last Des Moines Register poll in November, Klobuchar also finished fifth, with 6% support. She has not been able to capitalize on her Midwestern sensibilities and her record in neighboring Minnesota of winning in heartland counties Trump carried, yet Klobuchar contends that she is a viable alternative to the top four.
Even if Biden does not win in predominantly white Iowa on February 3 or New Hampshire on February 11 - the states with the first two nominating contests - he is expected to make up the ground once the race moves onto Nevada, then SC on February 29 and the 14 states holding contests on Super Tuesday on March 3, according to his advisers.
The findings are also discouraging for others, particularly New Jersey Sen. Booker, after campaigning aggressively in Iowa for almost a year, has support of just 3% of likely caucus-goers, according to the poll. Cory Booker. Despite his reputation as a rising star in the party and his considerable media exposure, he has consistently been overshadowed in this state's contest. Clearing 15% is important in Iowa, a state whose caucus system means supporters of candidates that do not meet a 15% threshold are forced to make a second choice.
But another candidate struggling in Iowa - California billionaire Tom Steyer - will be debating in Des Moines on Tuesday.
Biden, who was touring the state on Saturday as part of a two-day campaign swing, invested in Nevada early in his campaign and carved out a clear lead in opinion polls in the state.
Sen. Elizabeth Warren of MA will be to the left of Biden, and former South Bend, Indiana, Mayor Pete Buttigieg will be to the right of Sanders. Amy Klobuchar, broke over 1% among black voters. He had previously had a strong lead in the poll with 25 per cent, nine points ahead of Warren, who was then his closest competitor. Bloomberg, a late entrant into the race, is largely bypassing Iowa and other states that vote early. He and Warren, Buttigieg and Biden have each now placed as the lead in an Iowa poll conducted during a fluctuating and crowded 2020 campaign cycle among Democrats.
The poll still found room for movement among the candidates.