Robert Francis Kennedy Jr. should be damn glad his father cannot emerge from the ground at Arlington National Cemetery and give his son the whoopin’ he has earned.

Kennedy decided to suspend his presidential campaign and then did the unthinkable: He endorsed the Republican Party’s twice-impeached, four-times-indicted, convicted felon nominee for president of the United States … Donald Trump.

Junior, the scion of the nation’s premier family of partisan Democrats, turned his back on the principles championed by his forebears, namely his father, Robert F. Kennedy, his uncles JFK and Sen. Edward Kennedy and a host of aunts, siblings and cousins.

I am scratching my noggin over this endorsement. So help me, it makes zero sense.

RFK Jr. long has fancied himself as a man of action. He developed a nice environmental law practice and has been at the forefront of environmental causes almost since his graduation from law school. Trump doesn’t give a rat’s rear end about the environment.

And yet RFK Jr. is now backing the disgraced former POTUS.

What does RFK Jr.’s endorsement mean in terms of the election outcome? Probably not enough to matter. I won’t waste any time seeking to evaluate that particular consequence.

I only can imagine what Junior’s sainted mother, Ethel, must be thinking as she watches her son spit in the face of her beloved husband and throw his support behind a moron who stands before the nation and the world as the Republicans’ only nominee ever convicted of multiple felonies.

I may never catch my breath over this one!