Republican senators are grappling with how to rein in Medicaid spending even as some dismiss President Trump’s staggering proposed $1 trillion cut to the program.

Trump’s fiscal 2018 budget request released Tuesday calls for an additional $627 billion in Medicaid cuts over the next decade on top of $880 billion from the American Health Care Act, an Obamacare repeal bill that passed the House this month.

But some GOP senators doubted that the cuts could get through the chamber.

“Good luck,” said Sen. Orrin Hatch, R-Utah.

Sen. John Thune, R-S.D., said he was confused about whether the Trump cuts were an addition to the $880 billion in the American Health Care Act.

“I gotta figure out if they are assuming $840 billion and then another $600 billion on top of that,” he said.

Thune added that the budget is only “the administration’s ideas, and we will take into consideration their thoughts.”

Senate Majority Leader Mitch McConnell told reporters Tuesday that the Senate would draft its own budget, dismissing the budget Trump released Tuesday.

But Republicans are not shying away from big changes to Medicaid, the federal-state healthcare program for low-income Americans.

Thune didn’t like to use the word “cut” when describing Medicaid changes to reporters on Tuesday.

“When you say ‘cut,’ what I would argue is we have to come up with ways of reforming Medicaid,” he said. “I think that we all realize that these entitlement programs can’t stay on autopilot forever. There is going to require a certain amount of reform.”

Some Republicans shared ideas on Medicaid reform with Centers for Medicare and Medicaid Services Director Seema Verma during a GOP conference luncheon Tuesday, which Vice President Mike Pence also attended.

She shied away from endorsing key changes to Medicaid that lawmakers have been discussing, such as per capita caps and block grants.

A per capita cap gives states money on the basis of its number of Medicaid beneficiaries, while a block grant gives a state a fixed amount. One of those would replace the traditional fee-for-service model in place now.

The American Health Care Act would keep Obamacare’s Medicaid expansion in place until 2020 and then freeze new enrollment in the expansion. After that, a state could choose between per capita caps or block grants.

But Medicaid reform has been a contentious subject in the Senate, with lawmakers disagreeing on spending and when to end the expansion.

Washington Examiner Chief Congressional Correspondent Susan Ferrechio contributed to this report.