Headcount thus far on GOP Senators supporting immigration bill as of 5/11/13

The 844page Senate immigration bill has now been out for public inspection for a few weeks, but the numbers of GOP Senators that have publicly and officially backed the bill are still small.  Late last week, the amendment process, with 300 some amendments, began in earnest.  Marco Rubio (R-FL) head of the Gang of 8 has done a full court press with selling the bill to conservative voters and other conservative political leaders. 

Dan Balz at the Washington Post notes that Rubio's future political fortunes are very closely tied to this bill.  Balz also does a tally of GOP supporters so far in the senate:

At this point, according to one count shared by an advocate of reform, there are only four certain Republican votes for the measure — those of Rubio, McCain, Sen. Lindsey Graham (S.C.) and Sen. Jeff Flake (Ariz.). An additional five senators are currently considered possible supporters. How many more Senate Republicans the bill can attract will depend on what emerges from the amending process.

This is a good start, but these four known GOP supporters are part of the bipartisan Gang of 8 that wrote the bill, so one would hope they're on board with their own handiwork.  It is still early in the process and at the earliest, the bill would come to the Senate floor for a vote at the end of this month.  There are hopeful signs that more GOP Senators will sign on given the large number of conservative leaders who criticized the anti-immigration reform Heritage Foundation report.  But as Balz notes, "The size of an eventual Senate majority will influence what happens in the House."