"My focus is getting a large Republican vote," Schumer said, adding that "it would be wonderful if we could get a majority on both sides."
The goal is to give their bill so much momentum that the Republican-controlled House, which is more skeptical of reform, will have little choice but to take it up -- or something similar.
"If we were to pass this bill with, say, over 50 Democratic votes ... and only eight or nine Republican votes, it would pass, we would get to 60, but it would bode poorly for the House," Schumer said.
Also Thursday, in another sign of the resistance reform will face in the House, House Judiciary Chair Bob Goodlatte (R-VA) and immigration subcommittee Chair Trey Gowdy (R-SC), announced they would examine a series of smaller immigration bills as part of a possible "step by step" approach. Such a process is at odds with the comprehensive and bipartisan approach the Senate is taking. Goodlatte and others in his caucus have also expressed skepticism about a path to citizenship, although he has not definitively ruled the idea out.
Potential conflicts like these are the prime reason sponsors of the Senate bill are so gung-ho about passing their bill with peak momentum. The "Gang of 8" has insisted that immigration be tackled with a comprehensive bill, however, and McCain and Schumer both warned on Thursday that legislation that fell short on citizenship would be unacceptable on political and policy grounds alike.
"There's no way of getting this job done without giving people a path to citizenship," McCain said, noting that polls showed broad support for the idea "as long as you earn it"
"Any attempt to say in the House that you will not have a path to citizenship is a nonstarter," Schumer said. "And I say that unequivocally: it will not pass the Senate. I don't think it will get a Democratic vote."
Both McCain and Schumer addressed another possible roadblock to their bill: the Boston bombing, in which the two suspects arrived in the country as refugees as children.
The two said they were open to strengthening security provisions in their bill with amendments if any glaring policy failures arose out of the Boston investigation.
"I think its way too early," McCain said. "We dont know the lessons, we're finding out new info on a daily basis."
Schumer noted that the emerging backstory behind the attacks already suggests one area where their immigration legislation might have had a minor impact. As Homeland Security Secretary Janet Napolitano testified on Wednesday, Tamerlan Tsarnaev failed to trigger an alert on a terrorist watch list in January 2012 while flying to Russia because his name had been misspelled on his ticket. But under the new immigration bill, checks would be carried out through electronic swipes, not by inputting information manually.
"They would have known exactly who he was, they would have known someone on the [terrorist watch list] was both leaving and entering the country and it might have made a difference," he said "Our bill actually strengthens security and the events of Boston, if anything, should importune us to leave the status quo and go to a proposal like ours."