President-elect Donald Trump and Republican Congressional leaders are already promising to push through a new round of tax cuts to replace the 2017 cuts that expire in 2025. New tax cuts, they say, will be the first legislative–as opposed to initiatives by executive order such as new Trump tariffs–priority after the new president is inaugurated on January 20 2025.

With Republicans assured of a 53 to 55 seat majority in the Senate and likely to retain a majority in the House of Representatives, there’s not much Democrats can do to stop the cuts from becoming law.

A Senate filibuster won’t work because under the procedure known as budget reconciliation Senate Republicans can pass a budget with just 51 votes. And thus dodge the need to gain 60 votes to win a cloture vote to prevent a filibuster.

Republicans will be able to pass something like the $5 trillion to nearly $10 trillion in tax cuts over a 10-year period proposed by the campaign.

No matter if that will blow up the government’s debt problem.

But the reconciliation process imposes its own restriction on what can be included in a budget bill.

That means that although the tax cuts themselves will pass Republicans, face limits on what else they can attach to the budget bill. The Senate’s Byrd Rule prohibits “extraneous” provisions from any reconciliation bill. The rule defines extraneous as any provision that does not produce a change in outlays or revenues; or that produces changes in outlays or revenues that are merely incidental to the non-budgetary components of the provision; or that makes changes to Social Security.

Any Senator can raise a point of order against a provision they believe violates the Byrd Rule. The Senate Parliamentarian decides whether there is a Byrd Rule violation. If a point of order is sustained, the extraneous provision is struck from the bill. A 60-vote majority–the same number of votes needed to end filibuster–is required to waive a Byrd Rule point of order. The Byrd Rule effectively prevents the use of reconciliation for broad policy changes unrelated to budgetary matters.

Want to cut funding for the Department of Education or for the Environmental Protection Agency? You can do that in a reconciliation budget.

Want to direct the Department to change its protections for gay or trans students or to direct the EPA not to regulate a specific chemical or change its enforcement of pollution rules? You probably can’t do that as a provision to a budge passed by reconciliation.

I say “probably” because you can make an argument that just about anything produces a change in outlays or revenues. And it’s up to the Senate Parliamentarian, theoretically a non-partisan official, to rule on whether any challenged provision is in or out of bounds.

Expect a high degree of uncertainty.

But also expect the Trump tax cuts to pass Congress and be signed at the White House.