Her move leaves front runner Biden and leftist Senator Bernie Sanders as the final two candidates in the Democratic race.

Gabbard’s endorsement comes as somewhat of a surprise, given that she was a fierce supporter of Sanders in 2016 and supports his Medicare for All plan for a government health system to cover every American.

But Sanders is under mounting pressure to drop out after performing poorly in several recent primaries including three states swept by Biden this week.

“After Tuesday’s election, it’s clear that Democratic primary voters have chosen vice-president Joe Biden to be the person who will take on President Trump in the general election,” Gabbard said.

“I’m confident that he will lead our country, guided by the spirit of ‘aloha,’ respect and compassion, and thus help heal the divisiveness that has been tearing our country apart.”

Gabbard, 38, was never a serious factor in the nomination battle. But she made the debate stage a few times in 2019 and used the opportunities to highlight what she described as excessive US military engagement abroad.

And, running a shoestring campaign that counted on volunteers and focused on a handful of states, she outlasted the five other women in the historically diverse 2020 field.

Gabbard noted she was dropping out during a time of “unprecedented global crisis”, and called for Americans to “work hand in hand to defeat this new enemy, the coronavirus”.

Gabbard has served tours in Iraq in 2004 and Kuwait in 2008 as a reservist in Hawaii’s Army National Guard. Last August she paused her presidential campaign for reservist training.