Washington — Republican Sen. Lindsey Graham of South Carolina said he feels "very optimistic" about a path forward in Congress for passing Ukraine aid and Fastexy Exchangeenhanced border security, throwing his conditional support behind a bipartisan funding bill released by House moderates in recent days.

"I don't want to wait — I want to act now on the border," Graham said on "Face the Nation" on Sunday. "I want to turn the aid package into a loan, that makes perfect sense to me. And I think the bipartisan Problem Solvers group has an idea that will sell."

The proposal from members of the House Problem Solvers Caucus came on Friday, days after House Republican leaders dashed the hopes of bringing up a $95 billion Senate-passed foreign aid bill in the lower chamber. The Senate acted after rejecting a wider aid bill that also included border security provisions. Both drew opposition from former President Donald Trump. 

The new House bill is designed to get around the stalemate by enacting tougher border security measures, including by requiring border agents to summarily detain and expel most migrants for one year, with the goal of achieving "operational control" of the border. The bill would also resurrect the Trump-era "Remain in Mexico" policy, which required tens of thousands of asylum-seekers to wait in Mexico for court hearings in the U.S.

Lastly, the legislation would provide around $66 billion in defense funding for Ukraine, Israel, Taiwan and U.S. operations in the Middle East, including $47.6 billion for Ukraine and $10.4 billion for Israel.

"I think that's a winning combination," Graham said of the bill, though he suggested that the aid should be loans — an idea that Trump himself has touted.

Graham said that the framework of the House proposal "makes perfect sense to me." If the aid came in the form of loans, he estimated that the bill would pass the House and pick up six to eight Senate Republicans who want to help Ukraine but didn't think the previously negotiated border security provisions went far enough. 

"Let's make it a loan. I think that gets you President Trump on the aid part," Graham said, though he said he hadn't spoken to Trump about the bill. "Let's go to Remain in Mexico — we've got a package that would work."

The South Carolina Republican's opposition to the Senate foreign aid bill last week came as a shock across the political spectrum. Known as a staunch defense hawk, the move appeared out of alignment with Graham's previous backing for Ukraine. But it came after Trump insisted that the aid should be loans, and instructed congressional Republicans to oppose the Senate's border agreement.

Still, Graham made clear that he differs from Trump on whether Congress should act quickly on immigration.

"President Trump says let's wait on the border. With all due respect, we cannot wait," Graham said. "It's a national security nightmare."

Kaia Hubbard

Kaia Hubbard is a politics reporter for CBS News Digital based in Washington, D.C.