Whatever you might think of his politics, Bernie Sanders is a wonder — he has spent the past four years in tireless and relentless pursuit of his agenda, showing energy and stamina that would be impressive in people half his age.

Wednesday’s news that Sanders has had to suspend his campaign activities following the ­insertion of two stents into his heart in no way mitigates his ­astounding achievement since 2015. This one-time gadfly of all gadflies moved right into the center of American politics and shifted his party wholesale in his direction.

Still, Sanders’ health crisis — and it is a crisis, no matter what spin his people may want to put on it — may mark the first real turning point in the battle over the Democratic nomination.

The race has been remarkably static throughout 2019, featuring a Joe Biden lead followed by Sanders and Elizabeth Warren in second and third place. This has been true both nationally and in the four crucial early states (Iowa, New Hampshire, Nevada and South Carolina).

The last few weeks have seen Warren moving upward in the polls and Biden moving slightly downward. This has led to talk of a Warren surge and a Biden collapse, both of which are wild over-characterizations of relatively modest shifts. What we might see now is an end to the modesty.

It has been said that Biden is running as the key moderate in the race and has benefitted from the fact that Warren and Sanders have been splitting the support of the party’s leftist activists.

In the RealClearPolitics average, Biden is at 26% nationally — while Warren and Sanders added together get 41%.

Ten days ago, Biden was at 30 with Sanders/Warren adding up to 35, so you can see how the winds have been gently blowing voters away from Biden and mostly toward Warren.

If Sanders either finds it necessary to end his bid or continues it with his heart problems overshadowing his future, even his most loyal voters will have to look elsewhere. And the RealClearPolitics average puts them at 16.7% of the Democratic electorate.

It is doubtful they will look first to Biden. He is the establishment guy. Bernie is the anti-establishment guy who made his national bones facing down Hillary Clinton for being a corporatist shill.

How can Biden look any better in their eyes, especially when he has been explicitly differentiating himself from his party’s leftist candidates by opposing single-payer health care?

Nor is there any reason to ­believe they will be tempted by dark horses like Pete Buttigieg, the one candidate in the lower tier who seems to have any kind of a shot right now in one of the early states. His generally graceful and understated tone is like a negative image of Bernie’s raging passion when he speaks of, well, just about anything.

The Bernie voters who are with him ideologically really only have one place to turn, and that’s to Elizabeth Warren. She isn’t quite as left-wing as he is, but she is close enough for horseshoes.

Nor does she have his weird outsider appeal to disaffected young radicals, given her decades within the Holy of Liberal Holies as a tenured faculty member at the Harvard Law School.

But even if only 50% of his supporters move into Warren’s camp, it would be enough to propel Warren into a national lead outside the margin of error and give her pride of place in Iowa and New Hampshire both.

Biden’s hope at that point would be African American voters, who prefer him over Warren in massive numbers. Bernie Sanders’ inability to make headway with those voters in 2016 is what kept him from overtaking Clinton and seizing the Democratic nomination.

The problem for Biden is that at this point in the race, in September 2015, Hillary Clinton was 25 points up on Sanders — a gap he closed to a single point by April 2016.

Right now, Warren is only 2 points behind Biden nationally. If she makes Sanders-like gains in the next couple of months, she will leave him in the dust, African American voters or no.

Bernie Sanders should live to 120 (as long as it isn’t at my Passover seder). But his candidacy may not survive this. And if it doesn’t, the race is Elizabeth Warren’s to lose.

jpodhoretz@gmail.com