(CNN) – Speaking after a meeting with a group of House conservatives Wednesday, Sen. Marco Rubio of Florida continued to voice support for immigration reform legislation, but distanced himself from the Senate proposal he helped craft with the bipartisan "gang of eight".
Rubio was asked about his comments on a conservative radio show earlier in the day that he may vote against the Senate bill if the changes he wants don't pass. He didn't tell reporters on Capitol Hill he would vote against it, but did say, "If the changes don't happen, the bill can't pass. We'll keep working. We won't abandon the effort, we'll keep working to ensure that we have a bill that can pass."
Noting that he was asked to join the immigration effort in part to help bring Republicans on board, Rubio declared, "I can tell you that the bill as structured isn't going to pass the House, and it's going to struggle to pass in the Senate."
Republicans' concerns, Rubio said, center on border security and the bill's cost. Republicans are "generally prepared to do immigration reform so long as we can ensure that it doesn't cost the taxpayer money, and so long as we can ensure that there isn't another wave of illegal immigration in the future," Rubio said. "So that's what we're going to have to focus on, is winning peoples' confidence that that's what the bill will do."
Rubio joined a group of senators-both opposed and supportive of the Senate bill-for a meeting with a big bloc of House conservatives known as the "Republican Study Committee" Wednesday afternoon.
This marked the first major bicameral GOP meeting on the issue. Many members of the RSC have already said they plan to block any bill without stricter border security or legislation that includes a path to citizenship, but others in the group are open to comprehensive reform.
Sens. Jeff Flake (who's part of the "Gang of Eight" with Rubio on immigration), Rand Paul, Mike Lee, Ted Cruz, and Jeff Sessions also attended the meeting.
At the beginning of the meeting the senators spoke and alternated giving brief opening comments with House Judiciary Chairman Bob Goodlatte, Homeland Security Chairman Michael McCaul and Rep. Raul Labrador, R-Idaho – one of the 4 House Republicans in a bipartisan group trying to come up with a comprehensive immigration plan in the House.
Many House conservatives made it clear the Senate "gang of eight" bill is a total nonstarter with them, and cited the House Speaker John Boehner's position that he doesn't plan to bring it up for a vote. Many, including Goodlatte, pushed for the House to proceed with a series of immigration bills that focused on border security, and criticized the bill for not being tough enough on the subject.
Labrador told reporters after the meeting that overall, House conservatives don't like the Senate proposal, but are in favor of parts of it, but he stressed "I don't think you get anything out of the Senate without strong border security and we definitely don't get anything out of the House without strong border security."
The bill as currently written commits additional resources to southern border security and establishes a new system of metrics to measure border control effectiveness, but critics insist the plan is full of holes and will ultimately do little to help stem to the tide of illegal immigration.
A number of proposals to enhance border security before allowing the rest of the bill's provisions to take effect were rejected in the Senate Judiciary Committee's markup of the bill last month.
Speaking in the radio interview Wednesday, Rubio said if his added proposals fail to pass the Senate at large, he doubts the bill will get enough votes. Asked on the Hugh Hewitt show if he would still support it, Rubio said "no."
"If those amendments don't pass, then I think we've got a bill that isn't going to become law and I think we're wasting our time. So the answer is no. If they don't pass, then we have to keep working to ensure that we get to a bill that can become a law," he said.
An aide to Rubio pointed out that the senator has said all along the bill was only a "starting point" and would need improvement.
"He told Hugh last night that the bill currently doesn't have the bipartisan support it needs to become a law, and therefore it needs to be improved," the aide said.
Wednesday's bicameral meeting suggests that the Senate side is aggressively working to make sure they pass a bill that has a future in the House. As of now, House Republicans have expressed fierce opposition to the Senate version and a bipartisan group is working on their own bill in the House.
Goodlatte has said he wants to move immigration reform in pieces, not as a comprehensive package like in the Senate. Labrador, who's part of the RSC and a key GOP member of the House group working to finalize the immigration proposal, has repeatedly said the Senate immigration bill can't pass the House.
Republican Rep. Tom Price of Georgia, a key conservative leader in the House, told reporters Wednesday morning it "would be highly unlikely" at this point for the House to pass a path to citizenship because many do not trust the current administration to enforce the current immigration laws.
- CNN's Alan Silverleib, Paul Steinhauser, Ted Barrett and Ashley Killough contributed to this report.