The chairman of the House tax-writing committee said on Sunday he was confident that chamber would not go along with a Senate proposal to eliminate the deduction for property taxes, setting up a major flashpoint as Republicans aim to put a tax cut bill on Donald Trump’s desk before Christmas.

Republican leaders are moving urgently on what would be the first rewrite of the US tax code in three decades. Key differences promise to complicate the effort.

The House bill allows homeowners to deduct up to $10,000 in property taxes but the Senate proposal unveiled by GOP leaders last week would eliminate the entire deduction. The difference is among the biggest in the two bills to emerge so far.

The deduction is particularly important to residents in states with high property values or tax rates, such as New Jersey, Illinois, California and New York.

Kevin Brady, the Texas Republican who chairs the House ways and means committee, said he worked with lawmakers in those states to ensure the House bill “delivers this relief” and he was committed to ensuring it stays in the final package.

“It’s important to make sure that people keep more of what they earn, even in these high-tax states,” Brady said on Fox News Sunday.

Both the House and Senate bills would eliminate deductions for state and local income taxes and sales taxes paid. Chuck Schumer, the Senate minority leader, said Republicans should fully restore what is referred to as the “Salt” deduction, or millions of middle-class families would end up paying higher federal income taxes.

“The House’s so-called ‘compromise’ would be saying to the middle class, ‘We’ll only chop off four of your fingers instead of all five,’” the New York Democrat said in a statement.

A reduction in the corporate tax rate from 35% to 20% is a feature of both bills, but the Senate version delays the cut for one year. The US treasury secretary, Steven Mnuchin, said on CBS’s Face The Nation on Sunday he was confident the issue would not be a stumbling block to reaching an agreement.

“Obviously we would prefer if they kicked in sooner rather than later, but we’re going to work with the Senate on that issue,” Mnuchin said.

Mnuchin also rebuffed projections that the proposed tax cuts would increase the national debt. He said creating sustained economic growth of 3% or higher would generate trillions of dollars in additional revenue to the government, though he did not specify over what time frame that would occur.

“This is all about growth,” Mnuchin said.