The Nationals say they’re sick and tired of taking it. So, this year, they’re going to dish it out: to other teams that try to tread on them, but also within their own club, weeding out rock heads, malingerers and dead wood.

In baseball, this blend of external toughness and internal accountability usually coincides with victory. Few teams have strayed further from this ideal than the Nats of the last five years. But, so far, they’re walkin’ the walk.

“In the past, if you wanted to say something to another player you were in the minority around here. Now the scale has tipped. It’s the opposite,” said third baseman Ryan Zimmerman. “If you’re not one of those guys, it’s time for you to get out.”

The first half of this attempt at culture transformation was easy to see this week as the Nats, habitually nonviolent, engaged the notoriously pugnacious Cardinals in a 15-minute bench-clearing etiquette discussion.

The second half, the self-criticism that leads to true professionalism, is harder to detect, but it is underway here in every part of the locker room.

But first, the fun: On Monday, Njyer Morgan accidentally kicked Albert Pujols. Chris Carpenter drilled Laynce Nix. Livo Hernandez deliberately hit Colby Rasmus. So, ex-Nat Miguel Batista plunked Ian Desmond in the back. The old Nats might’ve turned the other cheek. The current Nats, not so much.

On his way to first base, Desmond stared down the Cards dugout, cussing Manager Tony La Russa. Both dugouts emptied, Nats first — in a novel twist. During the punch-free waltz, Nats Manager Jim Riggleman pointed his finger and hollered in the face of his friend La Russa, the skipper who may be the game’s top chip-on-the-shoulder intimidator for the last 30 years.

“That’s baseball,” said General Manager Mike Rizzo of the mini-fuss. Then, speaking generally, he added: “We’re not going to be pushed around. These new guys we brought in, they are not going to let teams ride roughshod over us.”

The Nats know that, if they want to build a tradition a fraction as good as the Cards’, they’ll have to erase a thousand forms of baseball malfeasance, all of which come under the heading of bad fundamentals and lack of focus.

“We have a much more veteran team, more professional,” said Zimmerman, ticking off the names of Jayson Werth (“he’s not afraid to say something”), Rick Ankiel, Alex Cora, Nix and Matt Stairs, as well as two sons of big leaguers, Jerry Hairston and Adam LaRoche. “It’s like we have a whole bunch more coaches.”

Throughout baseball, it’s assumed that ’11 will be a semi-lost season for the Nats while Stephen Strasburg heals, before Bryce Harper arrives and before the Lerners can spend the $100 million for a free agent pitcher that they were ready to offer Zack Greinke. To the Nats, however, it’s exactly the opposite. This is the year they need to find out who they are. Or can be.

“This is a prep year for when we take off next season when we are a professional team,” Zimmerman said. That sounds harsh, but it isn’t meant that way. Ryan’s just endured five years watching the Nats audition reclamation projects or troubled souls or develop a dozen youngsters simultaneously. The result: a guaranteed mess.

“This is not a good level to learn the game at — with 30,000 people watching every mistake,” said Zimmerman. “We haven’t had a team where you could ‘let us be us.’ Now, with all the veterans, we should be able to police the clubhouse ourselves. Jim can just be the manager.”

For the past season and a half, Riggleman has had to be much more — be a good cop in public, so he doesn’t damage fragile egos, but a bad cop in private because there was seldom anyone else to do the chew-out tasks.

“I’ve gotten on some guys very hard,” said Riggleman of his tenure. “It gets old when the teacher or parent is always the one doing the talking. It falls on deaf ears at some point. You need to hear it from your peers, too.

“But for the culture to change, you have to be willing to be policed. It can’t be an argument and people swinging on each other. You have to say, ‘Today, I’m the one being policed.’”

LaRoche has heard about the Nats’ reputation. “The manager shouldn’t have to come in and baby-sit,” he said. “That should be handled by your teammates. It’s happened a couple of times just recently. Sometimes other players have to lay it on you. There’ll be some hurt feelings for a couple of hours but we’re all grown men. We should be able to deal with it.

“ ‘Professional’ is a really good word,” added LaRoche. “You meet great guys who weren’t brought up the right way [in baseball]. A lot of selfishness comes out of that. But they just don’t know [any better].”

They will soon. In theory, there are now a dozen Nats, including old pros Pudge Rodriguez, Jason Marquis and Hernandez, who should be quick to tell ’em the correct way to play the ultimate game of detail. In baseball, pregame preparation and in-game concentration over six grueling months can separate teams of equivalent talent by a dozen games.

Zimmerman and ex-Padre Hairston talked about the Nats’ games with low-budget, 89-win San Diego last year. “They were head over heels mentally tougher than we were last year,” Zimmerman said.

The Nats, however, can’t just talk glowingly about how they’ve assembled players who should enforce a clean brand of baseball — a new Washington experience. They actually have to produce it.

This week, with Cards on first and second, the Nats put on the wheel play against the sacrifice bunt, with their shortstop racing to cover third base. Ball one. Next pitch, same situation, the Nats reversed strategy and the shortstop dashed behind the runner, who was picked off second base. All teams practice such plays in March. It’s fresh in mind. They get it right.

Will the Nats still get it right in a 5-2 game on July 27 that nobody on earth really cares about? Or will they throw the ball into center field because one player’s mind wandered?

And when they hash up that play, because sometimes everybody does, will those clubhouse police let it pass with a shrug? Or will the miscreant get an earful, not for the sake of ’11, but for all those future teams that may someday play games on July 27, or even Oct. 27, that mean the world?

A franchise’s identity is forged in thousands of details over a span of years until winning is in its DNA. The Nats have a long climb up baseball’s evolutionary ladder. It has to start somewhere. The Nats say this is that team.

Good. But if they don’t mind, we’ll all watch, too — from the stands, on TV, in the press box. Sometimes you need cops to watch the police.