Key Republicans are pushing back against a proposal from conservatives to use the upcoming omnibus spending bill to block funding for large parts of a refugee resettlement program, calling it impractical.

Rep. Michael McCaul (R-Tex.), chairman of the House Homeland Security Committee,  said Tuesday that the best way to confront President Obama over refugee policy in the wake of the Paris terror attacks is to include in the year-end appropriations package language from a recently passed bill that seeks to tighten the program’s security standards before Syrian and Iraqi refugees are allowed to enter the country.

A group of conservatives, led by Rep. Brian Babin (R-Tex.), is advocating for a more sweeping response to the attacks by blocking funding from being used to admit any refugees from Syria, the Middle East and North Africa until the administration can provide guarantees that the program is not being exploited by terrorists.

McCaul, who is part of a group of committee chairmen crafting the party’s response to the attacks, said that approach will not work because U.S. Citizenship and Immigration Services, the agency that oversees the refugee program, is funded through fees and is not covered by the appropriations legislation.

“The problem is, you can’t defund USCIS,” McCaul said.

“We kind of fell into that false narrative before, that you could defund it,” he added, referring to an earlier attempt to prevent implementation of an executive order from Obama regarding immigration policy

Republicans are eager to put a refugee bill on Obama’s desk soon.

Last month, the House passed a bill that would prevent Syrian and Iraqi refugees from coming into the country until the Obama administration certifies to Congress that steps have been taken to ensure none of them have ties to terrorist groups. The Obama administration opposes the legislation, arguing that there already are tough security protections in place for the refugee program and that the United States should be welcoming to people fleeing terrorism and despair in their country.

Senate leaders have said the bill would be difficult to move as a stand-alone measure through the upper chamber. That leaves the must-pass omnibus spending bill, which is needed by Dec. 11 to keep the government open, as the best vehicle for addressing concerns over the refugee program.

House leaders have not committed to what they may add to the omnibus, and more detailed discussions are expected to take place Thursday.

Babin recently sent a letter to party leaders, signed by 73 other Republicans, advocating going beyond the bill passed in the House by cutting off funding for key parts of the refugee program.

On Tuesday, he countered the argument that his proposal is impractical, saying that Congress could withhold money from the relevant programs run by the Health and Human Services and State departments.

“Refugees are flown over here by the State Department’s Bureau of Population, Refugees, and Migration,” Babin said in an e-mailed statement. “Just because a portion of the refugee resettlement program is fee-based does not mean Congress should simply relinquish its constitutionally mandated role in overseeing the expenditure of federal funds.”

But incorporating the already-approved bill into the omnibus would probably be the easiest approach for Republican leaders.

The House passed the refugee bill with a veto-proof majority — it had the support of 47 Democrats — and it would be difficult for Obama to veto an omnibus spending measure because of its inclusion.

“I think that’s the cleanest way to do it, and obviously it drew a lot of bipartisan support,” McCaul said.

This plan may also satisfy some of the conservatives who are pushing for a more sweeping approach.

Rep. Matt Salmon (R-Ariz.), House Freedom Caucus co-founder, who signed Babin’s letter, said Tuesday that he wanted the omnibus to reflect “exactly what we did in the vote that we just passed last week: make sure that we have a vetting process that actually is accountable.”

If the language of the House bill is included in the year-end spending package, it is all but certain to upset Democratic leaders, who have criticized GOP-led efforts to suspend refugee admissions in the wake of the Paris attacks. But they lost leverage in this debate when 47 House Democrats voted for the bill last month.

In the meantime, other measures to restrict the flow of visitors to the United States are forthcoming. On Monday, House Majority Leader Kevin McCarthy (R-Calif.) said the House hoped to vote on legislation to stiffen restrictions and scrutiny of travelers coming to the United States under a visa waiver program. McCaul said that legislation is being drafted and could be voted on next week.

Mike DeBonis contributed to this report.