Two Democratic senators threatening to derail Joe Biden’s agenda have been condemned by anti-corruption watchdogs for accepting a flood of money from Republican and corporate donors. Joe Manchin and Kyrsten Sinema present the last hurdle to the US president’s social spending and climate package after it was passed by Democrats in the House of Representatives earlier this month.

Having already pressured colleagues to cut the cost of the Build Back Better plan in half, the conservative duo continue to raise concerns about its $1.75tn price tag and sprawling ambition. Manchin and Sinema’s status as holdouts in a Senate evenly divided between 50 Democrats and 50 Republicans has guaranteed outsized influence and attention. It also appears to be lucrative.

In September, Sinema received a cheque from Stanley Hubbard, a billionaire Republican donor who is considering a similar contribution to Manchin because of their work to reduce the bill’s price tag, the New York Times reported this week. “Those are two good people – Manchin and Sinema – and I think we need more of those in the Democratic party,” Hubbard was quoted as saying. The newspaper also revealed Manchin, of West Virginia, and Sinema, of Arizona, travelled to an $18m mansion in Dallas for a summer fundraiser attended by Republican and big business donors who have praised their efforts to pare down the Build Back Better bill.

Manchin, for example, opposed popular provisions such as paid family leave and a clean electricity programme that would boost wind and solar power while phasing out coal and gas, while Sinema rejected an increase of personal and corporate income tax rates. Their stances have not gone unnoticed by Wall Street and wealthy conservatives. The $3.3m raised by Manchin’s campaign in the first nine months of this year was more than 14 times his haul at the equivalent stage last year, the New York Times added, while the $2.6m taken in by Sinema’s campaign was two and a half times what she netted over the same period in 2020.