“We want public hearings, a committee markup and an amendment process on the floor,” Rubio spokesman Alex Conant told CQ Roll Call on Monday. “We need to get buy-in from [everyone.] We want people to understand what’s in the bill and what’s not in the bill.” …

But Rubio advisers made clear that he views a lengthy, traditional process that includes hearings, a healthy committee markup and an open floor debate during which senators can offer amendments as key to his ability to build and maintain conservative support for a comprehensive immigration rewrite. Rubio does not have a specific timetable in mind. But anything viewed as “rushed” would violate promises he made to grass-roots conservatives and could cost his support, even if he is OK with the bill in principle.

President Barack Obama has warned that if Congress doesn’t act quickly, he’ll introduce his own immigration bill and exert pressure on lawmakers to approve an overhaul. And critics of Rubio’s deliberate approach will probably warn that slow-walking legislation will provide opponents time to assemble sufficient public opposition to sink the bill. …

He ascribes Congress’ past failures to approve immigration policy changes to a rushed legislative process. He believes that moving too fast on an issue as sensitive and complicated as immigration generates voter suspicion and makes it more difficult for broad, bipartisan support to build behind the effort. A bill negotiated in a backroom, in his view, could lead to surprises that scare members away from supporting the bill and result in fewer lawmakers taking ownership of the legislation.