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All kinds of things — personal and political — will drive the results of the 2020 presidential campaign.

Former Prime Minister Harold Macmillan put it best in 1957 when, after taking office, he was asked by a reporter what would affect his stewardship of the British government.

“Events, dear boy, events,” he replied.

In other words, circumstances are not static, change is constant, the future will be different from the past and it will have an impact on the present.

That reality of life comes to mind in the aftermath of an event that could have a major impact on who wins the Democratic Party’s 2020 presidential nomination.

U.S. Sen. Bernie Sanders, the Vermont socialist, sustained a cardiac event.

Specifically, Sanders was the recipient of two stents to facilitate arterial blood flow.

As a consequence, senior adviser Jeff Weaver said the Sanders campaign is “canceling his campaign events until further notice.”

Sanders “experienced some chest discomfort” during a campaign event Tuesday, leading to a medical checkup and the discovery that one of his arteries was blocked.

Of course, the question now is not whether Sanders can win the Democratic nomination but whether he’s healthy enough to serve as president should he be elected.

It’s already well known that Sanders, at 78, is the oldest candidate in an election scrum dominated by senior citizens.

The Sanders campaign can be expected to dismiss the cardiac event as a non-event. But it’s not — it will spawn a whispering campaign among his rivals that will take a toll on his credibility.

What’s done can be undone? Sanders and the age and health issue are now fully in play and sure to affect the campaign.