Bernie Sanders has done something unusual for him: He changed his mind.

While in most cases that’s a good thing (I have come out in favor of flip-flopping), this time it’s getting Sanders into trouble, because what he changed his mind about is releasing his medical records. But before you get too up in arms, we should realize that this issue is less clear-cut than it looks.

In a CNN town hall on Tuesday night, Sanders was asked if he would release his full medical records, which he said last year that he would do. He has released three letters, from his cardiologists in Vermont and the congressional physician, providing some details of his current health status and prior history.

But now, when asked if he’ll be releasing more records, Sanders answered, “I don’t think we will.”

Then his spokesperson went on TV and seemed to compare the request for medical records to the racist “birther” campaign against Barack Obama, saying this is reminiscent of “smear” campaigns against other candidates, “questioning where they’re from, their lineage.” That didn’t help.

So is Sanders really being evasive, even hiding critical information the public needs to know? Let’s look at this as objectively as we can.

On the surface, this seems closely analogous to the question of President Trump’s tax returns. In that case, not only does the public have a right to know what kinds of financial entanglements a president might have, but also there has never been a president for whom it was more important to get that information, given the complexity of his business interests, his history of tax fraud, and his clear belief that rules and laws don’t apply to him.

You could argue in turn that Sanders is the candidate — or at least one of the candidates — about whom the need for comprehensive medical information is most pressing. If he becomes president he’ll be 79 when he takes office, meaning he’d be 83 at the end of his first term and 87 at the end of his second term. Late last year he had a heart attack.

According to the actuarial tables, a 79-year-old man can expect to live nine more years. While Sanders seems extremely vigorous both physically and mentally for a man his age, it’s perfectly reasonable to have concerns and want to know as much as possible about his health.

And let’s be honest: We’re probably influenced on this question by the dishonesty and secretiveness of the current president. Even though the release of more than a doctor’s letter testifying to a candidate’s fitness didn’t used to be expected, with Trump in the White House we naturally want to know more than we’re currently being allowed. You’ll remember the comical letter Trump released from his doctor in December 2015, one that was so full of preposterous hyperbole that it was obviously dictated by Trump himself, as the doctor later admitted.

But exactly how much do we need to know? Are the letters Sanders has already released enough? The cardiologists tell us that he seems to have recovered well from his heart attack, and the congressional physician provides details on conditions for which he was treated in the past, as well as current information such as his blood pressure and cholesterol levels.

When we say a candidate should release his “medical records,” are we referring to documentation of every doctor visit and every procedure he or she has ever had? There are plenty of medical records that have no bearing on one’s performance in office, and which one ought to be able to keep private. The American people don’t really need to know the details of one candidate’s last pelvic exam or the unsightly rash another candidate got in his armpit in 1983.

That’s the trouble: We don’t have an established standard we can hold candidates to, and there isn’t a single document such as a tax return that we can demand.

But if we were to make such a standard, it would probably say at a minimum that we want the results of a recent physical, a history of any serious conditions the candidate has had in the past, details on any chronic conditions the candidate still has, and information on any medications the candidate is taking. Sanders can reasonably argue that he has provided much or all of that.

But here’s the thing: All this is only to give us a hint about what might happen in the next four years. We can’t know for sure. Among the candidates for president along with Sanders are the 73-year-old incumbent who seems to subsist on little more than KFC and thinks exercise saps your precious life force; a 77-year old former vice president; and a 78-year-old former mayor. Any one of them could experience serious health events in the next few years (as, of course, could any other candidate).

Does Sanders’s reluctance to release more information sound suspicious? Sure. But in the end, we have to just look at the information we have and decide whether we’re willing to take a risk on a candidate’s continued health. That risk is greater with Sanders than with some of his competitors. But we’re still just guessing about what might happen.

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