The White House has said it is "fighting" for the nomination of Indian-American Neera Tanden to lead the Office of Management and Budget as two crucial Senate committees abruptly postponed meetings on her confirmation.
Speculation was rife on Wednesday that the White House is struggling to get the required votes for the confirmation of Ms Tanden, amidst strong opposition from the Republicans and a few Democratic senators over her past Twitter outbursts against several lawmakers, including those from her own party.
The Senate Homeland Security and Governmental Affairs Committee and the Senate Budget Committee abruptly postponed votes on Ms Tanden's confirmation, scheduled for Wednesday.
"We're fighting for the nomination, and she (Tanden) and our team remain in close contact with senators and key constituency groups. She is an expert whose qualifications are critical during this time of an unprecedented crisis," White House Press Secretary Jen Psaki told reporters at her daily news conference.
If confirmed by the Senate, 50-year-old Ms Tanden would become the first person of colour to head the federal agency that prepares the annual budget of the US government.
Ms Tanden, Ms Psaki said, has rolled up her sleeves.
"She's very engaged and doing outreach to senators, to members on the Hill -- answering any questions they have and offering to do that. And we're doing the same," she said.
"There's one nominee to lead the budget department; her name is Neera Tanden, and that's who we''re continuing to fight for," Ms Psaki said when asked if the White House is seeking for options.
Ms Tanden reportedly deleted more than 1,000 tweets before her confirmation process started. She had apologised to senators during her confirmation hearings earlier this month.
President Joe Biden did not respond to questions on Ms Tanden during a media interaction on Wednesday.
"That's not the stage we're in," Ms Psaki said when asked if Ms Tanden has offered to withdraw her nomination.
"The stage we're in is working to continue to fight for her nomination. And as you know, it''s a numbers game. It's a matter of getting one Republican to support her nomination. We're continuing to do that outreach, answer questions they have, and continue to reiterate her qualifications," she said.
Politico reported that Ms Tanden's nomination for Office of Management and Budget director appeared to spectacularly collapse this week.
With Democratic Senator Joe Manchin and a number of moderate Republican senators announcing that they would oppose her nomination, The Washington Post said it has probably doomed her selection.
An op-ed in The Wall Street Journal said Ms Tanden's nomination looks as if it is going to fail Senate confirmation because of her tweets.
"In her years before the Twitter mast, Ms Tanden tweeted that Mitch McConnell was ''Voldemort'' and ''Moscow Mitch'', compared Ted Cruz unfavourably to vampires, called Tom Cotton a ''fraud'', said that Bernie Sanders - a frequent Tanden target - was helped by Russia in the 2016 Democratic primaries, and called Sen. Collins's reasons for voting to confirm then-Judge Brett Kavanaugh a ''pathetically bad faith argument as cover for President Trump's vicious attacks on survivors of sexual assault''," The Wall Street Journal said.
The New York Times said Tanden''s nomination is teetering.
Republican Senator Ted Cruz said Ms Tanden's nomination is on the rocks.
"We were on a path for Joe Biden to be the first president since Ronald Reagan to get every one of his cabinet nominees appointed, which didn''t make a whole lot of sense in a 50-50 Senate. With Manchin coming out against her, it's clearly on the rocks," he said.
Republican Senator John Cornyn told reporters that Tanden has "been bipartisan in her criticism of everybody" -- from Bernie Sanders to Joe Manchin and others.
"Clearly she was nominated because of her political credentials and frankly it's because of the lack of Democratic support that her nomination is likely to fail," he said.
Later in the evening, White House chief of staff Ron Klain told MSNBC they are "fighting our guts out" to get Tanden confirmed. If not confirmed, they won't try to make her acting director, but will put her in a role that doesn't require Senate confirmation.