Rand Paul is being pushed into a corner.
Just a day after both Paul and New Jersey Gov. Chris Christie made headlines with their comments on vaccinations, congressional Republicans and at least two potential 2016 challengers moved quickly Tuesday to declare their support for inoculating children against disease.
Most significant, the issue opened a rift between Paul and one of his most prominent allies in Congress: Senate Majority Leader Mitch McConnell.
Less than 24 hours after Paul questioned the use of vaccines, saying he'd "heard of many tragic cases" of vaccinated children "who wound up with profound mental disorders," McConnell pronounced himself "a big fan" of vaccination.
McConnell, noting that he suffered from polio himself as a child, said at a press conference Tuesday that if he were a parent of a young child he would vaccinate him or her.
Despite their rhetorical break, McConnell would not say whether vaccines should be mandated, stating again that as a parent he would support the practice. McConnell, who benefited greatly from Paul's support in his own Senate race last year, is expected to back Paul for the presidency in 2016.
Louisiana Gov. Bobby Jindal, who is expected to run against Paul and Christie for president in 2016, put out a strong statement of his own Tuesday urging parents to vaccinate their children. "Every one," he said.
"I have no reservations about whether or not it is a good idea and desirable for all children to be vaccinated," Jindal said in the statement. "There is a lot of fear-mongering out there on this. I think it is irresponsible for leaders to undermine the public's confidence in vaccinations that have been tested and proven to protect public health."
Sen. Marco Rubio, another 2016 hopeful, made the same case to reporters Tuesday.
"Absolutely, all children in America should be vaccinated," Rubio said, according to NBC News, later adding: "There is absolutely no medical science or data whatsoever that links those vaccinations to onset of autism or anything of that nature."
Similarly, House Speaker John Boehner said Tuesday that he believes "all children ought to be vaccinated." However, he added that he does not necessarily believe that Congress will need to pass a law mandating vaccinations.
The quick moves by congressional Republicans pit Christie and especially Paul against their party's leaders in Congress, a position Paul is generally more accustomed to than the establishment-backed Christie.
Both Christie and Paul later said they had vaccinated their own children but added that parents should have a choice in whether to follow their examples.
The recent vaccination debate within the party comes as a measles outbreak has raced through California, infecting nearly 100 children.
Though many of the Californians who decline to vaccinate their children come from the most-liberal areas of the state, House Minority Leader Nancy Pelosi also made a strong pro-vaccination argument Tuesday.
"While I'm sympathetic to concerns "¦ it is a public health issue," Pelosi said. "The fact is that children should be vaccinated."
Alex Brown contributed to this article