Washington has not exactly won a reputation for fiscal discipline over the last few decades, as both Republicans and Democrats passed bills that have, bit by bit, degraded the nation’s finances.

But the legislation that Republicans passed through the Senate on Tuesday stands apart in its harm to the budget, analysts say. Not only did an initial analysis show it adding at least $3.3 trillion to the nation’s debt over the next 10 years — making it among the most expensive bills in a generation — but it would also reduce the amount of tax revenue the country collects for decades. Such a shortfall could begin a seismic shift in the nation’s fiscal trajectory and raise the risk of a debt crisis.

The threat is a reflection of the fact that Senate Republicans have voted to make tax cuts that the party first passed in 2017 a permanent feature of the tax code. That means the growth in the country’s debt, already at levels economists find alarming, would only accelerate as the bill shaves down the country’s main source of money.

“We are looking at the most expensive piece of legislation probably since the 1960s,” said Jessica Riedl, a senior fellow at the Manhattan Institute, a conservative think tank. “The danger is that Congress is piling trillions of new borrowing on top of deficits that are already leaping.”

Historically, lawmakers have been unable to make such a large change in the country’s finances without bipartisan support, helping contain how much debt is added at a time.

That is because reconciliation, the special legislative procedure that Republicans used to avoid the filibuster in the Senate and pass the bill along party lines, has long included the requirement that bills cannot add to the debt for more than a decade. But Republicans decided to disregard that rule, relying on an accounting gimmick to argue that the $3.8 trillion cost of extending the 2017 tax cuts is actually zero and therefore they can continue indefinitely.