Dr. Ben Carson was just starting to sound like one of the sane passengers in the GOP 2016 clown car, at least when it comes to the topic of vaccinations... and then he went on Jake Tapper's show this Tuesday afternoon.

Ben Carson Blames Measles Outbreak On 'Undocumented People':

Potential 2016 candidate Dr. Ben Carson, who has expressed support for strict vaccination policies, on Tuesday linked the measles outbreak in California to undocumented immigrants.

CNN's Jake Tapper asked Carson if parents' decisions not to vaccinate their children led to the outbreak.

"It is a good example of what happens," Carson responded.

But he then suggested that the outbreak may have started with undocumented immigrants.

"These are things that we had under control. We have to account for the fact that we now have people coming into the country sometimes undocumented people who perhaps have diseases that we had under control," he said. "So now we need to be doubly vigilant about making sure that we immunize them to keep them from getting diseases that once were under control."

According to the World Health Organization, about 93 percent of children in Honduras, Guatemala and El Salvador, from which a majority of undocumented children have emigrated from, have gotten a measles vaccination.

When asked how to enforce immunization in the U.S., Carson noted that many schools require certain vaccinations.

"We already have policies in place at schools that require immunization reports. A lot of people are put off when they hear the word government force. And perhaps there's a better way to put these things," he said, adding that the benefits of immunizing children have been proven.

Ed. Note: Someone should tell Ben Carson that Mexico's vaccination rate is 98 percent, compared to the US rate of 90 percent.