As Joni Mitchell sang 50 years ago, “Don’t it always seem to go that you don’t know what you’ve got ‘til it’s gone.”

Mitchell’s iconic song, “Big Yellow Taxi,” was about protecting the environment. But it’s also apropos, as Mainers head for the voting booth next week, to protecting our children.

I’ve tried – as a citizen, as a journalist and, most important, as a grandparent – to consider both sides of Tuesday’s statewide referendum. It asks us whether we want to repeal a new law that removes non-medical exemptions from vaccines required for children to attend school or college and for adults to work in health care and child care environments.

As a member of this newspaper’s editorial board, I met last month with proponents of the repeal campaign, which goes under the dubious name “Reject Big Pharma: Vote Yes on 1.”

Since then, I’ve read in this newspaper about their ongoing efforts and listened to them on statewide radio. And yes, I’ve seen all those roadway signs implying that by supporting their cause, I’d be giving a much-deserved punch in the nose to the pharmaceutical industry.

Yet, as the vote fast approaches, I’m still struck by the opacity – if not the outright duplicity – of their argument.

I just listened to a recording of that editorial board meeting with referendum campaign managers Cara Sacks and Sarah Kenney and campaign consultant David Boyer. The session, which lasted well over an hour, left my head spinning.

Let’s start with the obvious: When it comes to diseases like measles, mumps, polio, diphtheria, chicken pox and whooping cough, vaccines have without question made the world a better place.

One need only look back 50 or 60 years, as a number of Maine physicians have on our op-ed pages in recent months, to realize how quickly we as a society forget the real threats that all children faced before vaccines became a bulwark against death and crippling disease all those decades ago.

But that’s not what I heard during our sit-down with the “Reject Big Pharma: Vote Yes on 1” crowd.

I heard, among other things, that when you ask the average Maine doctor about potential vaccine side effects, he or she can’t answer because they’re not taught those things in medical school.

I pressed for an example of a medical school that ignores such things. Boyer referenced a news release in which a single doctor said he “got half a day” of instruction on vaccines. Sacks mentioned “the physicians we’ve talked to, some in my family, some through this (campaign), whatever.” No one cited a specific medical school curriculum or, for that matter, a doctor willing to publicly make that claim.

I heard that Maine has the highest rate of childhood mental health problems in the nation. I later confirmed that to be true, according to an article published online last year by JAMA Pediatrics.

“So, that’s related to vaccines?” Editorial Page Editor Greg Kesich asked the group, failing to see a connection between immunizations and mental disorders.

“It could be. I don’t know, I’m just saying,” Sacks replied.

I heard that doctors in Maine, particularly those working under such large systems as MaineHealth and Northern Light Health, risk discipline or outright dismissal if they grant medical exemptions – still permitted under state law – to children whose health is legitimately threatened by vaccines. But again, when it came to naming names, the closest we got was Sacks’s reference to her recent “very underground meeting” with a group of doctors who can’t come forward for fear of being fired.

I heard that the same pharmaceutical companies who brought us the opioid crisis line the pockets of those physicians who boast 100 percent vaccination rates among their child patients.

Once again, no specifics. Nor, for that matter, did I hear any rational connection between opioids and vaccines – beyond the implication that both originated with the pharmaceutical industry and if one was driven by a perverse profit motive, so must be the other.

I heard more than one reference to the “69 doses” of vaccines that the federal Centers for Disease Control and Prevention recommends between a child’s birth and 18^th birthday. Yet when I dug into the “Reject Big Pharma – Vote Yes on 1” website, I came across their own admission that “there are not 69 required doses for school entry in Maine … yet.” (For the record, the state requires 16 vaccine doses between kindergarten and 12^th grade.)

I heard references to religious objections to vaccines. When asked what major religions prohibit the use of vaccines, however, the answer was that none do. Rather, Sacks said, “it’s really left up to that personal belief or personal relationship, so there are many groups that feel strongly about that.”

Now a word or two about what I didn’t hear.

I didn’t hear that doctors, nurses and other health providers choose their professions to help make and keep people healthy, not make them sicker.

I didn’t hear that while the “herd immunity” so critical to keeping the aforementioned diseases in check is currently around 95 percent statewide, it is by no means cast in stone. Pockets with much lower vaccination rates already exist at some schools in Maine – and the non-medical opt-outs nixed by the Maine Legislature last year served only to make that slope all the more slippery.

Finally, for all I heard about parents who worry, with precious little science to back them up, that vaccines pose a bigger danger to their kids than the diseases they were created to prevent, I didn’t hear much about the flip side of this coin: Parents with immuno-suppressed children who can’t be vaccinated and thus face heightened risk from every child whose parents opt out simply because vaccines conflict with their narrow world view.

Sarah Staffiere of Waterville is one such parent. Her 6-year-old son, Gabe, has a rare genetic disorder that could land him in the hospital, or worse, if he were exposed to an unvaccinated classmate with a disease that could have been prevented.

“I scream into the pillow at night, but I have to let him be a kid, live his life. We don’t want him in a bubble,” Staffiere told reporter Joe Lawlor in last weekend’s Maine Sunday Telegram. “The danger to our son is not hypothetical.”

The bottom line: Vote no on Tuesday. We’re talking about our kids’ safety here – and we won’t know what we’ve got ‘til it’s gone.