The conservative darling's fall from grace has been thoroughly documented after his ill-fated effort to overhaul the nation's immigration system in the Senate last year, and Rubio has been hard at work trying to repair his image before a possible presidential run in 2016.
But resident wingnut and birther-in-chief Donald Trump won't let him nor the voters he would certainly have to woo, forget it.
Trump attacked Rubio for wanting to "let everyone in," claiming that undocumented immigrants admitted to the country legally wouldn't even vote Republican.
"Immigration. We're either a country or we're not. We either have borders or we don't," Trump, who often rails against "amnesty," told conservative attendees at Thursday's Conservative Political Action Conference.