New Jersey Governor Chris Christie’s presidential hopes got a boost on Friday when Mitt Romney dropped out of the 2016 race leaving some room for establishment donors to choose someone other than Jeb Bush to support. But his greatest weakness was never really the fact that there is stiff competition for the backing of business, Wall Street, and party leaders around the country. Nor is Bridgegate the only burden that he must carry around with him in his quest for the White House. His problem is the same propensity for blunt and unpredictable remarks that made him a YouTube star vaulting him to national attention. We are reminded of that today as the backlash over remarks he made about vaccination during a visit to Britain have created exactly the wrong kind of attention for a person running for president.

In Britain for a trade mission, Christie was asked about the problem created by a growing minority of American parents who are refusing to vaccinate their children due to a combination of misinformation about side effects and bizarre theories about health. Here’s what he said:

Mr. Christie, when asked about the connection between the new measles cases and parents who object to the long-recommended vaccine against it, said that he and his wife had vaccinated their four children. He called that “the best expression I can give you of my opinion.”

But he added: “It’s more important what you think as a parent than what you think as a public official. I also understand that parents need to have some measure of choice in things as well. So that’s the balance that the government has to decide.”

Mr. Christie said that “not every vaccine is created equal, and not every disease type is as great a public health threat as others.”

On its face, that sounds like he is neutral about parents exercising their “choice” to refuse vaccinations and “balance” in the response of the government to this trend.

Given the menace to public health that the anti-vaccination effort has caused, that brought down the opprobrium of many concerned citizens as well as a host of political kibitzers, including gloating Democrats, on Christie’s head.

In response, Christie “clarified” his remarks on Sunday night:

“The Governor believes vaccines are an important public health protection and with a disease like measles there is no question kids should be vaccinated,” Christie’s office said in a statement. “At the same time different states require different degrees of vaccination, which is why he was calling for balance in which ones government should mandate.”

That’s a big improvement on his original off-the-cuff remark but, to be as blunt as the governor usually is, the damage is already done.

It doesn’t matter that Christie may have meant something very different from what it seemed like he was saying when he was talking about “choice” and “balance.” Perhaps he was thinking of vaccines for rare diseases that might not be worth the effort to get everyone to take them. But whatever it is that he meant, there is no doubt that he demonstrated that while his loose lips helped build his reputation as a political truth-teller, they could also sink him.

As to the substance of the matter, put me down as one of those who think that the only sensible response of any leader to questions about vaccines should be an adamant call for all citizens to take advantage of them. To talk of choice or to indulge our libertarian instincts on the issue of vaccination is a huge error in judgment. As a popular Internet meme puts it, “if my kid can’t take a peanut butter sandwich to school, our kid shouldn’t be able to bring an easily preventable disease.”

Of course, we won’t elect a president based on his or her ability to have a consistent and smart record on vaccination. This is a one-day story about a gaffe, not a political disaster.

But it is one more piece of evidence for Republicans to take account of when weighing whether Christie is presidential material. He may keep telling us that a tough-talking blue state governor is exactly what the GOP and the country needs. But what he is also doing is reminding us that this is a man who often speaks candidly and at length when he should stick to talking points or say nothing. It’s bad enough to be the guy who tells people to “sit down and shut up” when challenged on the stump. But it’s far worse to be the guy who says something dumb or easily misinterpreted. If Christie doesn’t believe me, he can ask Mitt “47 percent” Romney if a tendency to make gaffes can be an obstacle to the White House.

This foolish kerfuffle probably won’t stop Christie from running for president since he is clearly burning to do so. But it will, along with every other verbal mistake he has already made and those that have yet to leave his mouth, be held against him by GOP donors, activists, and voters. If there was a vaccine for gaffes, Christie should obtain it. But it may already be too late.