Sen. Bernie Sanders (I., Vt.) is leading an effort to pressure lawmakers into including another round of stimulus checks in the next round of coronavirus relief.

“It will be an outrage for Congress to go home for the holidays when tens of millions of working families are living in desperation,” said Sanders to reporters on Tuesday.

A bipartisan group of lawmakers has been trying to finalize a $908 billion compromise bill for the past week — but as it currently stands, that plan does not include another round of $1,200 direct payments.

“I know that there’s considerable public support for it [stimulus checks], but right now we’re targeting struggling families, failing businesses, healthcare workers,” said Sen. Susan Collins (R., Maine), who is involved in crafting the bipartisan proposal.

On Tuesday afternoon, Sanders and five Democratic senators sent a letter to their Democratic colleagues in the Senate, urging them to demand that any new coronavirus relief proposal contains stimulus checks.

“We very much appreciate the hard work that has gone into the current $908 billion proposal being drafted by a number of Democratic and Republican Senators. But, simply stated, given the horrific extent of the current crisis and the desperation that working families all over this country are experiencing, this proposal does not go anywhere near far enough,” the senators wrote in the letter.

Sanders, Sen. Elizabeth Warren (D., Mass.), Sen. Ron Wyden (D., Ore.), Sen. Kirsten Gillibrand (D., N.Y.), Sen. Jeff Merkley (D., Ore.) and Sen. Ed Markey (D., Mass.) also pushed their colleagues to reject provisions that “give a liability shield to corporations who threaten the health and safety of workers and customers.”

Liability protections — a Republican “red line” — have been a key sticking point throughout stimulus negotiations.

Progressives like Sanders, Rep. Alexandria Ocasio-Cortez (D., N.Y.) and others have been pushing for more direct aid — but there is some conservative support for the idea as well. Sen. Josh Hawley (R., Mo.) has told President Trump he should veto any coronavirus relief bill that doesn’t include stimulus checks.