In an extraordinary display of political power in the evenly split 50-50 Senate, a single senator is about to seriously set back an entire presidential agenda.

“We’re frustrated and disappointed,” said Sen. Dick Durbin, the majority whip. “Very frustrated,” said another Democratic senator granted anonymity to frankly discuss the situation Thursday…

Democratic senators have grown weary of their colleague, whose vote they cannot live without — but whose regular chats with Republican leader Mitch McConnell leave them concerned he could switch parties and take away their slim hold on power.

“Mr. Manchin and the Republicans and anybody else who thinks that struggling working families who are having a hard time raising their kids today should not be able to continue to get the help that they have, then that’s their view and they’ve got to come forward to the American people and say, ‘Hey, we don’t think you need help,’” said Sen. Bernie Sanders, the independent from Vermont. “Let them tell the American people that.”