The US Senate passed a $1.5 trillion tax cut package early Saturday, with Republicans overcoming wavering legislators in their ranks and concerns about cost and a process which quickly pushed the legislation with little time for review.

The chamber voted 51-49 for the nearly 500-page bill after legislators received a rewritten version, with significant changes from the original bill that passed two Senate panels last month, only hours earlier.

Speaking on the Senate floor ahead of the vote, Minority Leader Chuck Schumer challenged “a process and a product that no one can be proud of and everyone should be ashamed of”. He said changes “under the cover of darkness” would “stuff even more money into the pockets of the wealthy and the biggest corporations while raising taxes on millions in the middle class”.

Congress’s Joint Committee on Taxation projects that the bill will add $1 trillion to deficits over a decade, even after accounting for economic growth.

However, the GOP succeeded after ensuring that several senators who had expressed concern — or even said they would not accept the bill — shifted to announce support this week. They included Susan Collins of Maine, Lisa Murkowski of Alaska, Ron Johnson of Wisconsin, and Jeff Flake and John McCain of Arizona.

The only Republican to vote No was Bob Corker of Tennessee, objecting to the additional burden on the Federal Government’s deficit.

Collins swung into line, after a promise from Senator Majority Leader McConnell that he will support two bipartisan bills seeking to stabilize individual insurance markets under the Affordable Care Act.

Johnson and Senator Steve Daines of Montana were assured by a more generous tax break for companies organized as pass-through entities, benefitting smaller businesses.

Flake obtained an agreement for work on “fair and permanent protections” against deportation of the young undocumented immigrants — “Dreamers” — under the Obama Administration’s Deferred Action for Childhood Arrivals.

Murkowski was given a provision to open up the Arctic National Wildlife Refuge in Alaska to oil and gas drilling after a decades-long battle over the environmental effects.

Political scientist Norman Ormstein summarizes: