There are two versions of Robert F. Kennedy Jr. and since I don’t know which version would reign I’m ambivalent about his nomination as U.S. Health and Human Service secretary.

President-elect Donald Trump has tabbed Kennedy for that post, subject to Senate confirmation.

(Which seems likely, given the Republican majority.)

Prior to the election, Trump vowed that if voters returned him to the White House he would encourage Kennedy to “go wild on health.”

I would prefer a more measured approach from a cabinet secretary than a phrase more typically associated with college students on spring break.

However, nearly a decade into his political career I no longer overreact to Trump’s inevitable hyperbole.

I’m not worried that Kennedy, encouraged by Trump’s bloviating, will wreck America’s health care system, which despite its flaws — notably its gargantuan cost — has immense capacity for good.

(Consider: If your heart starts misfiring like a piston deprived of oil, or you hack off a couple of fingers while procuring some kindling, I doubt you’d rather be in any other country.)

Yet certain of Kennedy’s statements about vital topics, and in particular childhood vaccinations, are so asinine as to give me pause.

And his responses to criticism about some of those claims, although inevitably more nuanced and ostensibly thoughtful, don’t reassure me.

That’s the bad Kennedy.

The good Kennedy speaks with similar passion about other subjects, such as America’s obesity epidemic, its growing prevalence of chronic disease and its poor performance, compared with other developed countries, in such measures as average life expectancy.

(We’re pretty good at fixing ailing hearts and other organs in America but unfortunately too many of us need such life-saving intervention.)

As a member of the Trump administration, with the figurative megaphone accompanying the position, Kennedy could have a positive influence as he decries the ersatz nutrition of processed foods and seeks to interrupt the sometimes incestuous relationship between pharmaceutical companies and federal regulators who are supposed to put more value on our health than on their profits.

But plenty of qualified people could spread the same message from a political pulpit.

People who, as any rational person must, recognize that childhood vaccines are truly a medical miracle, and probably the greatest health care achievement in human history.

Kennedy, though he strives to sound reasonable about vaccination, has made ludicrous statements on the topic that no amount of seemingly thoughtful response can offset.

Recently he insisted that he would not “take vaccines away from anybody.”

But this is a meaningless platitude, since states, not the federal government, set vaccination requirements (typically for attending public schools).

As recently as July 2023, in an interview on Fox News, Kennedy said: “I do believe that autism does come from vaccines.”

He didn’t specify which vaccine. The most prominent example of a specious connection between inoculations and autism was a 1998 paper published in the British medical journal The Lancet linking autism to the MMR vaccine — measles, mumps, rubella.

The Lancet retracted the paper after it recognized, as it ought to have done before publication, how shoddy the research was.

Moreover, multiple peer-reviewed studies have since shown, beyond any reasonable doubt, that the MMR vaccine doesn’t cause autism.

When confronted about claims that he is an “anti-vaxxer,” Kennedy usually responds with something similar to what he said in the Fox News interview: “All I’ve said about vaccines is we should have good science.”

Vaccines, Kennedy said, should just be treated like other medications in balancing the risk with the efficacy.

The blatant flaw in this reasoning, of course, is that we’re not talking about something newfangled and unproven.

Billions of doses of vaccine have been given over the past several decades, and the results are as irrefutable as gravity. Diseases that prior to widespread immunization infected and sickened millions of children each year, and killed hundreds or thousands (measles probably was sort of amusing in the 1950s unless you died from it), were all but eliminated.

Kennedy, in trying to sound reasonable — who, after all, doesn’t want to ensure that medicines cure rather than harm us? — acts as though this issue hasn’t been settled as regards vaccines.

But it has been settled.

The problem here is that Kennedy, an already prominent person who would be more so if confirmed by the Senate, can influence people.

His similarly inane statements about COVID-19 vaccines — he said, among other things, that people who took the vaccine had a 21% chance of dying within six months — undoubtedly persuaded some people to eschew a vaccine that could potentially save their lives.

(Yes, the Biden administration, including the president himself, overestimated the benefits of vaccines in preventing COVID-19 infection and mild sickness. But overhyping the benefits is preferable to discouraging people from protecting themselves from a serious, potentially life-threatening, illness.)

The harmful effects of this nonsense already seem to be spreading. Rates for childhood vaccinations have declined in many places. Measles, which in effect disappeared from the U.S. a couple decades ago, has returned. The numbers are still quite small, to be sure, but when it comes to completely preventable infections our goal, as it was not so long ago, should be eradication.

Kennedy certainly satisfies Trump’s appetite for defying convention.

But I don’t think we need a person who ignores medical reality running the $3 trillion federal agency tasked with helping Americans stay healthy.