Senate Republicans are discussing provisions for their version of the bill to overhaul the U.S. tax code that would differ significantly from the House’s legislation.

The discrepancies — which range from changes to the current state and local tax deduction to when corporate tax cuts take effect — could tee up a battle among the two chambers and the administration that might complicate the timeline the GOP is pursuing to get a bill to the president’s desk.

The Senate bill is expected to be released this week — likely Thursday, once the House Ways and Means Committee completes its markup. While lawmakers say the legislation will ultimately achieve the same overall goal as the House bill (to provide tax relief to the middle class and U.S. corporations), how the two chambers accomplish it could be quite different.

Part of the reason for that is the nature of the Senate. Unlike the House, the chamber does not have many Republican members from largely Democratic states. That makes a battle over removing provisions popular in blue states — like the deduction for state and local taxes — far less contentious.

Conversely, the Senate could, for example, face more pressure on issues affecting student loans and private colleges, given that universities are often the largest employers in most states.

“While the basic framework … will be within the same parameters of the House bill, I’d expect a number of the details to be different,” Kansas GOP Sen. Jerry Moran said. “You represent an entire state. It has a different outcome than representing a congressional district.”

Based on conversations with senators and GOP aides, here are four areas where the Senate tax bill might differ most markedly from the House. The Senate Finance Committee, which is writing the bill, declined to comment for this story.

State and local tax deduction

The Senate is still weighing whether to include a full repeal of the state and local tax deduction. While the repeal would generate substantial revenue to use to offset cuts elsewhere in the legislation, some senators remain skeptical.

“I am concerned about eliminating the deduction for income and excise taxes and capping the property tax,” Maine Republican Susan Collins said Monday. 

Such a provision faced immense pushback in the House and was ultimately scaled back to allow individuals to deduct up to $10,000 in property taxes. A full repeal is likely a nonstarter in that chamber, creating a possible major point of contention between the House and Senate.

Phase-in cuts to corporate tax rate cut

A major tenet of the GOP tax framework is the reduction of the corporate tax rate. Both the House and the Senate are aiming to lower it from the current 35 percent to 20 percent, but how that’s achieved could differ.

Senate Republicans are considering phasing in the corporate tax cuts over several years. Such a proposal was weighed on the House side, but ultimately dropped amid pushback from both U.S. businesses and the White House.

The House also considered phasing out the cuts due to budget constraints. It was ultimately kept as a permanent repeal in the latest version of the legislation. That decision, however, could create so-called Byrd Rule problems for the House bill in the Senate and spur that chamber to take a different approach.

The rules governing the fast-track budget reconciliation process mandate that a specific provision cannot add to the deficit outside the 10-year window, one reason why House Republicans chose to sunset some provisions in their bill. Preliminary budget analyses show a permanent cut in the corporate tax could raise deficits after 10 years.

The Senate is also still considering including some version of a proposal from Finance Chairman Orrin G. Hatch of Utah that would allow corporations to push dividends to shareholders as a mechanism to lower their corporate tax rate, commonly known as corporate integration.

No estate tax repeal

Senate Republicans also continue to weigh keeping the estate tax and instead doubling the exemption for money individuals or families leave to heirs.

The House bill would double the exemption until 2023, when the estate tax would be repealed permanently.

Mortgage interest deduction

House Republicans have proposed lowering the cap on the mortgage interest deduction to the first $500,000 of new mortgage debt, a move that spurred resistance from National Association of Home Builders.

While it is possible that cap could be raised before the legislation reaches the House floor, the Senate is considering leaving the deduction as is. Currently, a family can deduct interest paid on the first $1 million in home loans.