When you watch the video of Bryce Harper being hit by a 98-mph fastball and charging Hunter Strickland for, say, the fifth time, pay attention to the character who will tell you all you need to know about right and wrong, good and evil, in that situation. Not Harper, incensed and flinging his helmet as he tore after the pitcher. Not Strickland, all 6 feet 4 and 220 pounds of him, ready to absorb whatever Harper had to offer.

Nope. Watch Buster Posey, the San Francisco Giants catcher, the Giants’ leader. Watch him do . . . nothing.

That should provide an indication of the Giants’ instantaneous reaction to this Memorial Day ridiculousness. The rules of engagement in baseball, whether they’re written or not, are pretty clear: pitcher with beef, legitimate or not, throws at batter; batter gets [ticked] off, stares and/or points at pitcher; catcher steps between batter and his own pitcher; batter is forced to power through catcher if he’s to get to pitcher.

And yet the next time Posey steps between Harper and Strickland will be the first. Posey was closer to wandering into the stands to flag down the popcorn vendor than he was to protecting Strickland. Home plate umpire Brian Gorman, who is 57 years old, beat Posey to the mound — because Gorman actually took a step or two to try to defuse the situation.

“Those were some big guys tumbling around,” Posey said afterward, explaining his absence from the fray, according to the San Francisco Chronicle.

This is baseball, from roughly the time of Old Hoss Radbourn to the present, and whatever Manny Machado or Dustin Pedroia or Bryce Harper think about it, it isn’t changing soon. This sport has policed itself long before Ty Cobb went flying, spikes up, into second base. And it polices itself still. That might seem silly. When those 98-mph fastballs get toward heads — rather than the back side, where Harper was hit — it can seem downright dangerous. But, as Nationals outfielder Jayson Werth told reporters, “It’s part of the game.”

Given that, what happened Monday afternoon at AT&T Park in San Francisco isn’t terribly surprising. But who, exactly, was Strickland policing? Think whatever you want to about Harper — and there are a wide variety of opinions, including in the Nationals’ own clubhouse. But Harper’s crimes against Strickland — two monstrous postseason homers, and we’ll get to the specifics shortly — came three seasons ago.

Three seasons ago.

So listen to Harper, speaking sense.

“It’s so in the past that it’s not even relevant anymore,” Harper told reporters after the game. “They won the World Series that year.”

There’s the key concession: Hey, Hunter, I tagged you twice in the 2014 National League Division Series. But you have a ring that I don’t have. I’ll tip my cap and try to get the best of you next time.

When you think about the specifics of what went down that October — again, three seasons ago — Strickland’s fastball directly at Harper on Monday seems even more absurd. Harper first faced Strickland leading off the seventh inning of Game 1 at Nationals Park, with the Nats already down 3-0. He drilled a 2-1 fastball out to right, a moonshot that he admired because, well, it was worthy of admiration.

The Giants won the game, 3-2.

Strickland and Harper met again, this time in the seventh inning of Game 4, with the Giants leading both the series and the game 2-1. Harper got another fastball, this one at 3-1, and he drilled it into McCovey Cove, the Barry Bonds territory beyond AT&T Park’s right field wall. It was, arguably, the biggest homer in Harper’s career, and he bellowed as he rounded the bases, chirped when he got back in the dugout.

The Giants won the game, 3-2. The Giants won the series, 3-1.

Again, listen to Harper, thinking big picture.

“I don’t even think he should be thinking about what happened in the first round,” he said. “He should be thinking about wearing that ring home every single night.”

The Giants who played in that series who also played Monday afternoon include not only Posey, but first baseman Brandon Belt, second baseman Joe Panik and shortstop Brandon Crawford. Those players, forever, will be known as World Series champions in the Bay Area. Their revenge wasn’t plotting to plunk Harper three years later. It was a tad more clever — and more painful, where Harper’s concerned. It was winning the whole damn thing that fall.

There are just so many indications that Strickland was the only one thinking about this as a revenge situation. It’s not like this was the first time the two teams had faced each other since that series — again, three seasons ago.

“Hunter waits three years to get him,” Nats second baseman Daniel Murphy, not a member of Washington’s 2014 team, told reporters after the game. “If the Giants thought it was that egregious, Bryce would’ve gotten one the next season. So he waits three years to get him? Completely uncalled for.”

Completely uncalled for. Harper was suspended four games, because that’s how these things work. You’re not supposed to fight for yourself, even when a tiny sphere is hurled at your body. Strickland was suspended six, even though he protested that he was trying to work Harper down and in, rather than leaving a fastball over the plate, because we know what Harper has done to those pitches in the past.

That there’s not a Nat or a Giant who believed Strickland’s version isn’t surprising, because that’s how baseball works. What’s telling is there wasn’t a Giant who defended Strickland’s action, either. The rules of engagement, stupid or not, were established long ago. Buster Posey knows them. So watch him stand behind the plate as Harper went after Strickland, and you learn everything you need to know about who was right and who was wrong on Monday afternoon in San Francisco.