If former Vice President Joe Biden secures the Democratic presidential nomination, 15% of Sen. Bernie Sanders' supporters will vote for President Donald Trump's reelection, according to an ABC News/Washington Post poll.

If accurate, that would represent a slightly larger defection than occurred after the bitter battle between Sanders and former Secretary of State Hillary Clinton in 2016, when 12% of Sanders voters broke for Trump in the general election.

The good news for Biden is that in spring 2016, an ABC News poll found 20% of Sanders supporters said they would vote for Trump over Clinton, and far fewer ended up doing so. And 80% of Sanders' supporters said they would back Biden over Trump, according to the poll.

The 15% who said they plan to vote for Trump represents just 6% of Democrats and voters who lean Democratic, according to ABC News. Trump won 8% of Democrats in 2016.

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Biden holds a more than 300-delegate lead over Sanders, who has said he intends to continue his fight for the nomination despite the tough odds of overcoming Biden's lead. The ABC/Post poll found Biden with a 16-percentage-point advantage (55%-39%) over Sanders among registered Democrats and independents who lean Democratic.

In a hypothetical general election matchup, Biden narrowly topped Trump by 2 points (49%-47%), which is well within the poll's 3.5-percentage-point margin of error. That signals a dramatic tightening of the race from October, when an ABC/Post poll found the former vice president with a 17-point lead over Trump among registered voters.

Fox News poll:Biden leads Trump by nine points

Supporter enthusiasm for Biden is lower than Trump

Trump held a solid advantage over Biden in voter enthusiasm. Fifty-three percent of Trump's backers said they would be "very enthusiastic" to cast their votes for him, while 24% of Biden's supporters said the same for their candidate. That is the lowest for any Democratic presidential candidate in 20 years in an ABC/Post poll. Among Sanders supporters who said they back Biden in November, just 9% said they were very enthusiastic about doing so.

The president also held an edge over Biden when it came to the economy, where 57% said they approved of Trump's performance. When asked who they would trust more to handle economic matters, 50% said Trump and 42% said Biden.

Biden has been highly critical of Trump's response to the coronavirus outbreak, but Trump narrowly bested Biden on that issue in the poll as well. Forty-five percent of Americans said they trusted Trump more to deal with the crisis, while 43% said they had more faith in Biden.

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When it came to health care, however, Biden was more trusted by a wide margin of Americans (52%-39%) over Trump.

On Friday, an earlier portion of the poll was released that showed for the first time more voters approve of Trump's job performance than disapprove (49%-47%). Other polls have also shown a rise in Trump's approval rating amid the battle against the coronavirus and the RealClearPolitics average of his approval numbers is at its highest since he took office.

The poll was conducted from March 22-25 by telephone from a sample of 1,003 adults.