Senate Democratic Leader Chuck Schumer (N.Y.) vowed in a letter to Democratic colleagues that the party will oppose the massive bill intended to implement President Trump’s agenda “with everything we’ve got.”

“This partisan monstrosity is nothing short of a billionaire handout paid for by American families and we will fight it with everything we’ve got,” Schumer wrote in a Sunday letter to Senate Democrats.

He called the bill, which Republicans are moving through the budget reconciliation process, a “ruthless power grab by the nation’s most wealthy” and vowed that “Senate Democrats will use every tool at our disposal in this battle and we will enlist American families to join this fight.”

Schumer alleged Republicans are planning to “run rough-shod over the Byrd Rule” that determines the scope of any legislation that is eligible to pass under the Senate’s reconciliation process, a fast track that allows the majority to pass legislation with a simple majority vote without having to overcome a filibuster.

“In the Senate, our committees have been working overtime to prepare for the Byrd Bath, targeting the litany of policies included in the Republican plan that are in clear violation of the reconciliation rules and in some cases, an assault on our very democracy,” he wrote.

Schumer singled out a provision that “House Republicans snuck in” to the package that would “restrict the authority of federal courts to hold government officials in contempt when they violate court orders.”

He said Senate and House Democrats “must be united” to fight what he called “this assault on working families,” noting he spoke Sunday afternoon with House Democratic Leader Hakeem Jeffries (N.Y.) about “ways our caucuses can fight back together.”

He also said Senate Democratic Steering and Policy Committee Chair Amy Klobuchar (D-Minn.) has invited the ranking Democrats on key House committees to meet with the Senate Democratic caucus to share their “firsthand insight from their process and key Republican fault lines.”

Schumer highlighted provisions in the bill that would cost “millions of Americans” their health insurance by restricting subsidies under the Affordable Care Act and making changes to Medicaid’s eligibility and work requirements.

He also pointed to changes to the Supplemental Nutrition Assistance Program, which he said would cut $300 billion from federal food aid programs, and the termination of clean energy subsidies and tax breaks.

“Republicans are hell bent on making the Trump tax cuts for billionaires permanent, exploding the federal debt by adding over $50 trillion to it in the next 30 years,” he wrote.