WASHINGTON (AP) -- The increasingly contentious debate over childhood vaccination spilled over into the 2016 campaign with two presidential hopefuls getting a lesson on how unexpected issues can become stumbling blocks.
New Jersey Gov. Chris Christie and Kentucky Sen. Rand Paul, both weighing bids for the Republican presidential nomination, struggled this week to articulate their views on the emotionally charged vaccination controversy. Christie, in the midst of a three-day trip Britain, canceled plans to speak to reporters Tuesday after his comments a day earlier caused a stir.
Paul, a libertarian-leaning eye doctor, pushed back on criticism of his initial assertion that he was aware of "many tragic cases of walking, talking, normal children who wound up with profound mental disorders after vaccines." He issued a statement Tuesday denying immunizations cause disorders, saying they were just "temporally related." He also posted a photo on Twitter of himself getting a booster for a vaccine.
While the vaccination debate has long stoked passions, the matter has taken on new resonance amid a frightening measles outbreak that has sickened more than 100 people across the U.S. and in Mexico. The outbreak has revived the discussion about parents who choose not to vaccinate their children, some out of fear that vaccines can lead to autism and developmental disorders -- a claim that has been vigorously debunked by medical researchers.
It's unclear whether the vaccine issue will have a long shelf life in a White House campaign that is only just beginning. But the ways prospective candidates handle unanticipated issues can help determine whether those subjects blow over or become nagging distractions that contenders can't shake.
"Every day you want to go out with a message to voters, and every day there are a dozen trapdoors you don't want to fall into," said Robert Gibbs, a top adviser for both of Barack Obama's presidential campaigns. "If you look at Chris Christie and Rand Paul , they fell into the trapdoors yesterday."
Christie's and Paul's assertions that parents should have some choice in basic vaccinations have put other potential 2016 contenders on the spot on a topic that was largely absent from political discussions until this week and does not break down along party lines.
Three potential Republican candidates voiced their support for vaccines Tuesday: Sen. Marco Rubio of Florida, Louisiana Gov. Bobby Jindal and Wisconsin Gov. Scott Walker.
Likely Democratic candidate Hillary Rodham Clinton took to Twitter, saying, "The science is clear: The earth is round, the sky is blue, and (hashtag)vaccineswork. Let's protect all our kids."
A Pew Research Center survey conducted in August found that 68 percent of Americans think vaccination should be required for all children, while 30 percent think parents should be allowed to decide.
Associated Press writers Jill Colvin in Cambridge, England, Scott Bauer in Madison, Wisconsin, and Philip Elliott, Ken Thomas and AP News Survey Specialist Emily Swanson in Washington contributed to this report.
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