It’s a classic political move: Do something you know an opponent doesn’t want to do and challenge him to match you.

That’s what Mike Bloomberg did Thursday to Bernie Sanders, the front-runner in the Democratic primary contests.

Thirty-six hours before the South Carolina primary Bloomberg is trying to raise renewed concerns about the health of Sanders, who suffered a heart attack in October. The New Yorker’s campaign released detailed blood flow numbers from Bloomberg’s latest physical exam last summer.

Both men are 78, older than anyone ever entering or exiting the White House.

That’s one year older than Joe Biden, five years older than Donald Trump, eight years older than Elizabeth Warren, 16 years older than Tom Steyer, 18 years older than Amy Klobuchar and 40 years older than Pete Buttigieg.

In their chests both Sanders and Bloomberg have stents, tiny plastic or metal tubes placed inside an artery to enable full blood flow to and from the heart.

Bloomberg’s clogged artery was discovered 20 years ago during a routine physical exam and stress test. Since then, he has served three terms as mayor of the nation’s largest city.

Sanders, on the other hand, had no symptoms until experiencing chest pains at a Nevada campaign event in October and was rushed to a hospital. There, he was diagnosed as having suffered angina and a myocardial infarction, or heart attack, in which some of the heart tissue died.

At the time Sanders pledged to release his full medical records before primary voting began, saying:

The people do have a right to know about the health of a senator, somebody who’s running for president of the United States. Full disclosure…It will certainly be before the first votes are cast.

After two weeks, Sanders resumed campaigning. Now, three states have voted, a fourth on Saturday and 14 more next Tuesday. Sanders says there won’t be any more information coming beyond his doctors’ letters saying he is now in good health and able to fulfill presidential duties.

Thursday night a Sanders spokesman said, “The (doctors’) letters that we’ve released are very thorough.”

Sanders dodges further inquiries by challenging any questioner to follow his demanding schedule. Primary and general election campaigns are indeed brutally demanding physically and mentally, even for younger candidates.

That’s the point, to test wannabe commanders-in-chief before what feels like an endless stream of voter audiences, night flights and hotel rooms that could be anywhere.

It’s a nice try by the Bloomberg campaign, at least a public relations gambit to raise questions in voters’ minds about Sanders’ health and what he might be hiding.

But with Sanders in so deep on refusals, it seems unlikely to prompt any real change beyond one or two day’s worth of negative media coverage, like this post.

Once not so long ago, a barrage of demands for transparency on personal health or tax records would have forced disclosure, typically copies of a detailed medical report and the appearance of a doctor authorized to disregard confidentiality and discuss personal health issues.

But traditional media, their powers weakened by savage online competition, crippling financial conditions and widespread public distrust, no longer seem to possess the clout to confront the stubborn refusals of emboldened public figures.