Which Democrats are attracting donors in race to tackle Donald Trump in 2020?

Many Democrats have already entered the race to be the party’s 2020 presidential nominee but some are faring better than others in the all important task of raising the money needed to fund a campaign.

The totals for the first quarter, which ran through to March 31, are the first measure of how candidates are performing.

Details for the entire field will not be known until candidates file their required disclosures with the Federal Election Commission by April 15.

The senator from Vermont, who showed surprising fundraising ability in his challenge to eventual Democratic presidential nominee Hillary Clinton four years ago, raised more than 18 million US dollars in the 41 days between his official campaign launch and March 31, giving him 28 million dollars cash to hand.

Those totals are expected to lead the Democratic field, putting pressure on other heavyweights, including Mr Biden, who is still deciding whether to run and who is navigating accusations that he has acted inappropriately toward women.

Besides Mr Sanders, Senator Kamala Harris of California put up an impressive 12 million dollar haul.

Former US Representative Beto O’Rourke of Texas did not offer a fundraising total, but aides said he raised more than one million dollars over the weekend and previously said he raised more than six million dollars in his first 24 hours as a candidate.

Mr Sanders’ haul shows that his base is just as enthusiastic as it was four years ago.

In fact, it may be growing.

The senator’s campaign noted that of his 525,000 unique donors, about 20% are new, about 100,000 are registered independents and about 20,000 are registered Republicans.

As impressive as Mr Sanders’ fundraising has been, it is not as large as previous presidential contenders who were more reliant on big donors.

In her first quarter as a candidate ahead of 2016, Mrs Clinton topped 45 million dollars.

In 2007, when then-senator Barack Obama and Mrs Clinton were beginning their long battle for the 2008 nomination, the favourite Mrs Clinton opened with an initial fundraising quarter of 36 million dollars, while the underdog Mr Obama pulled in 26 million dollars.

Ms Harris is the only candidate of that group to release her fundraising totals.

But the biggest winner may be Pete Buttigieg, an unlikely headline-grabber even among a group of lesser-known candidates that includes governors and members of Congress.

The 37-year-old mayor of South Bend, Indiana, raised seven million US dollars, calling it “a great look for our first quarter”.

That might be an understatement.

Such a sum ensures Mr Buttigieg can finance a legitimate campaign operation for months as long as he is not a profligate spender.

Mr Buttigieg said he has almost 160,000 unique donors, a mark that meets the new grassroots fundraising thresholds that the Democratic National Committee has set for candidates to qualify for the initial summer debates.

The eventual Democrat nominee will take on President Donald Trump in 2020.