Senator Elizabeth Warren is preparing to quit the Democratic race for the party's presidential nomination setting the field for a straight contest between centrist former Vice President Joe Biden and Senator Bernie Sanders, a self-declared socialist.
Warren, who is from the party's left wing, was going to announce her withdrawal after faring poorly in the primaries - the intra-party elections - to select the candidate to confront President Donald Trump in the November elections, several media reports quoting sources in her campaign or close to her said on Thursday.
While an ideological consolidation is taking place in the party, it was not certain who she would back after backing out of the contest even though she is ideologically closer to Sanders with whom she has clashed.
Three moderate candidates - Senator Amy Klobuchar, former small-town Mayor Pete Buttigieg and billionaire businessman Michael Bloomberg - have quit the race and endorsed Biden after poor performance in the party polls.
Another candidate, hedge fund billionaire Tom Steyer, has also pulled out.
Of those who have shown up nationally, only Hindu American member of the House of Representatives Tulsi Gabbard remains in the race, although she has polled around one per cent or less of the votes in the 18 states where the party polls have been held.
She is a leftist and was Sanders's supporter in 2016.
The quest for Democratic nomination is now confined to two septuagenarian white men, Biden, 77, and Sanders, 78, all the women, except Gabbard, and non-whites having left the race.
Senator Kamala Harris, who is of Indian and Jamaican African descent, showed early promise and fared well in party debates but quit in December even before the party polls got underway.
Biden, who performed poorly in the first two party polls leading to questions about his viability, made a stunning comeback after the primary in South Carolina and the 14 on Tuesday, winning ten of them.
Sanders was shown ahead of him in national opinion polls and in many of the 14 states, but won only in four states.
The final blow for Warren was losing in even her home state of Massachusetts on Tuesday.
Many in the Democratic Party establishment and moderates fear that if Sanders were to be the party candidate in November he might lose because of his self-declaration that he is a socialist and also take down Congressional candidates belonging to the party.
That has led to the other moderates dropping out to back him.
Warren has accused Sanders of telling her that a woman does not have a chance of winning the presidential election and both clashed publicly over this. Sanders has denied saying it,
Hillary Clinton was the first woman presidential candidate of a major party in 2016, but lost to Trump.
Warren has toned down some of her left-oriented stands, declaring herself a "capitalist" and backing down on proposals for a government monopoly on healthcare by offering a role for private insurers.