“Ted was … a supporter of legalizing people that were in this country illegally,” Rubio said Sunday on CBS’ “Face the Nation.” “And so the bottom line is there isn’t that big a difference between him and I on how to approach immigration.”

Rubio’s statement left some observers dumbfounded. It’s not just that Rubio voted for the Gang of Eight bill (in addition to writing it) and Cruz voted against it. Even a cursory look at the Gang of Eight debate shows issue after issue in which Cruz and fellow opponents pointed out problems with the bill, only to have Rubio and the Gang reject their views. A June 4, 2013 “Dear Colleague” letter signed by Cruz, Jeff Sessions, Charles Grassley, and Mike Lee sets out a long list of amendments — concerning border security, treatment of illegal immigrant criminals, immediate legalization, a path to citizenship, and other issues — that outlined enormous differences between Cruz and Rubio.

Rubio supporters sometimes point out that such differences were in the past — more than two years ago — and that Rubio’s position on comprehensive immigration reform today is different than it was then. But first, it is unclear just what parts of the 1,197-page Gang of Eight bill Rubio now views differently, and second, on “Face the Nation” Rubio suggested that positions in the past are relevant to today’s debate. ‘If you’re going to attack someone on a policy issue,” Rubio said, “you need to be clear about where you stand on the issue and where you’ve stood in the past.”