Now that a measles outbreak in California has prompted a bizarre debate on the merits of vaccines, we’re learning where some prominent 2016 Republican presidential contenders stand on the issue of immunizing kids.

Of all the candidates, Senator Rand Paul—an ophthalmologist by training—has given the most misleading information by far. He suggested that it’s safer to space out vaccines over time, rather than give newborns shots all at once—a recommendation that isn’t backed by the Centers for Disease Control and Prevention and Institute of Medicine, which find no reason to delay vaccines. As Jonathan Cohn notes, anti-vaccine advocates have a 100-plus-year history of feeding the public misinformation like this. New Jersey Governor Chris Christie has also been unclear exactly where he falls: he's insisting that parents should have a choice in vaccinating their kids, but also says that all kids should receive a measles vaccine.

On the other hand, of the 2016 GOP field, Florida Senator Marco Rubio has had the most rational answer so far: He unequivocally supports vaccination. "Absolutely, all children in America should be vaccinated," he told reporters on Tuesday. “There is absolutely no medical science or data whatsoever that links those vaccinations to onset of autism or anything of that nature."

Journalists (myself included) quickly noted that Rubio normally doesn't think of himself as a scientific expert. 

In 2009, the Miami Herald asked him whether climate change was manmade. His answer: “I’m not a scientist. I’m not qualified to make that decision.” In 2012, Rubio repeated the line to GQ when asked how old the Earth is. "I'm not a scientist. I'm not qualified to make that decision. There's a significant scientific dispute about that." Rubio has proven no more informed on either issue when he’s been asked in subsequent interviews. 

It's clear that Rubio is neither an expert on climate change nor on evolution. He is also not an expert on the atmosphere, oceans, and fisheries, although he's now the chairman of a science subcommittee in the Senate that oversees these matters. His entrusted job as a senator is to base policy on what the experts say. And they say that—just like the overwhelming medical consensus on the need for vaccines—there is agreement that carbon pollution drives climate change and that evolution exists. Rubio only prioritizes science when it suits him, which is common behavior for Republicans and even some Democrats. That is as much a disservice to the public as Paul's own comments.