Senior Democratic officials were stunned and more than a little angry to hear West Virginia Sen. Joe Manchin's Sunday announcement that he will not vote for President Joe Biden's Build Back Better legislation, effectively killing Democratic hopes of passing the "landmark" social spending legislation.

Manchin's pledge, delivered on Fox News Sunday, caught the White House nearly totally off guard, especially on the heels of Biden's phone calls with the senator on the topic, a White House staffer told the Washington Examiner.

WHITE HOUSE: MANCHIN'S 'NO' ON BUILD BACK BETTER CONTRADICTS HIS DISCUSSIONS WITH BIDEN

"Sen. Manchin has expressed his problems with Build Back Better for months, but his about-face on Sunday was an outright betrayal of his conversations with the president last week," that person said in a statement.

Politico reported Sunday evening that Manchin notified the administration of his decision a half-hour ahead of his interview with Fox's Bret Baier, prompting the president's top advisers to rush and try to change his mind. Manchin reportedly spurned calls from the White House in the lead-up to the interview.

"I’ve always said this, Bret. If I can't go home and explain it to the people of West Virginia, I can't vote for it, and I cannot vote to continue with this piece of legislation. I just can’t. I’ve tried everything humanly possible. I can’t get there," Manchin said on Fox News Sunday. "This is a 'no' on this legislation."

Two senior Democratic aides say that after his talks with the president, Manchin offered a counterproposal to Biden worth roughly $1.8 trillion. The proposal included two major wish list items for left-liberal Democrats, a decade of funding for universal pre-K, and billions to fund new climate initiatives but did not include an extension of the expanded child tax credit, one of if not Biden's top priority for the plan.

Those aides told the Washington Examiner that after Manchin gave the White House his counter, he and Biden agreed to table negotiations until the new year, even if it meant stretching out the legislative process until the spring. Manchin's Sunday "performance" shows he was not negotiating in good faith with the president.

White House press secretary Jen Psaki was even more forceful in her Manchin denouncement.

"Sen. Manchin's comments [Sunday] morning on Fox are at odds with his discussions this week with the president, with White House staff, and with his own public utterances," she wrote on Sunday. "If his comments on Fox and written statement indicate an end to that effort, they represent a sudden and inexplicable reversal in his position and a breach of his commitments to the president and the senator's colleagues in the House and Senate."

"Just as Sen. Manchin reversed his position on Build Back Better [Sunday] morning, we will continue to press him to see if he will reverse his position yet again, to honor his prior commitments and be true to his word," she continued. "In the meantime, Sen. Manchin will have to explain to those families paying $1,000 a month for insulin why they need to keep paying that, instead of $35 for that vital medicine."

Furthermore, when asked by reporters if the president feels "betrayed" by Manchin, Psaki claimed that her Sunday statement "made clear" the White House's position.

"I understand the questions here, but our focus is on moving forward," she stated. "I think our statement yesterday made clear what the course of events were over the last couple of weeks, and that was important for the American people to know and see that, but he considers Sen. Manchin a longtime friend, and our focus is on moving forward and getting this done."

Washington Democratic Rep. Pramila Jayapal, the chairwoman of the Congressional Progressive Caucus and one of the top lawmakers working directly with Manchin on a Build Back Better compromise, claimed Monday that Democrats can no longer "trust what Sen. Manchin says."

"The senator called me this morning. I took his call, and there's nothing I have said here that I didn't say to him," she told reporters Monday afternoon. "I think he probably has never wanted to do the Build Back Better act. I think we boxed him into a corner, and I think he was looking for a way not to do it."

Jayapal concluded her Monday press call by calling on Biden to pass as much of the plan as possible through executive action.

CLICK HERE TO READ MORE FROM THE WASHINGTON EXAMINER

Meanwhile, Senate Majority Leader Chuck Schumer vowed to bring the legislation to the floor "very early in the new year so that every member of this body has the opportunity to make their position known on the Senate floor, not just on television."