When you’re a young NFL player and you fail a test for recreational drugs, that’s an indiscretion and a wake-up call.

When you flunk again, but this time you are one of only 11 players, out of nearly 2,000 in the NFL, who fail in training camp after the lockout, that illustrates the old expression, “Sometimes a drug test is really an IQ test.”

But when you know you’ve failed both those tests, when you know the league is monitoring you as one of those 11 dopes, when you know a third failure could result in a one-year suspension from the league, and you still fail another test in the regular season for recreational drugs, that is a character exam.

Did Trent Williams and Fred Davis flunk all three tests? According to reports in various media, including the Post’s sources, second-year tackle Williams, 23, and fourth-year tight end Davis, 25, will be suspended for the last four games of the Redskins’ season for what appears to be exactly that sequence of drug-testing disasters, likely for using marijuana.

Out of roughly 2,000 players, after the union and the league finished months of who-got-caught-how-many-times-and-when negotiations, only two players received any discipline at all. And they are both Redskins — with major quarter-of-a-season suspensions. That’s quite a distinction. Imagine how much worse than everybody else you have to be to get that booby prize.

Don’t pass this off with, “Which is Cheech and which is Chong?” Don’t stop your analysis at “that’s why they call it dope.” Don’t say, after a 34-19 loss to the Jets with the Redskins now at 4-8: “Who cares? Lost season.”

Perhaps there are franchises and coaches that are in strong enough shape to withstand such irresponsible and selfish behavior from a pair of their best young players. But the Redskins under Coach Mike Shanahan, in the 12th year of the Daniel Snyder era, are not such a team. This was a year to rebuild, to assemble a responsible locker room, to show modest progress on the field but with greatly increased accountability and lessened drama off it.

So, if all accounts are true, a tackle making $7.852 million this year and a tight end on pace for a 1,000-yard season in his contract year were using recreational drugs in a season when they knew they’d already been nailed twice. What is it about “against the law” and “against league rules” and “violation of duty to employer and teammates” that they don’t understand?

This was the kind of team-character body blow and lack-of-leadership stumble that the Redskins did not need. Clearly, two of the Redskins’ most important young players are not listening to the message.

It can be overcome, eventually. But the Redskins had enough to overcome already. Only five teams in the NFL have a worse winning percentage over the last 20 years. And Shanahan, who picked Williams as his first draft pick in his first year as coach, has won just one playoff game since ’99. If you’re 1,000 miles from D.C., “Redskins” is just a laugh line. Now this.

“We have player reps that inform us of things. People make mistakes . . . [But] I don’t know the details,” defensive tackle Barry Cofield said. “We’ve got too much on our plate to think about other things, or it will slow us down.”

Since no official announcement has been made and Davis may contest any suspension, the Redskins avoided comment. But the locker room simmered with annoyance. “We are grown men. We make choices,” safety Reed Doughty said. “And everybody has to be accountable to the team.”

Perhaps 12-year veteran Mike Sellers, whose first three seasons exposed him to the remnants of the mature ’90’s Redskins, had the best long-term perspective. “I remember when the whole room [was adults],” Sellers said. “Right now, this is still a young locker room. Once they get a few more years under their belts, then they’ll figure out what this league is about.

“I don’t know what’s going on [with suspensions],” Sellers added, “but when I first broke in, I was that knucklehead. The old Redskins kept me straight. Brian Mitchell, Terry Allen and ‘the sheriff’, Stanley Richard.”

Perhaps the Redskin with the most right to be furious was the most understanding — London Fletcher, still leading the defense in his 14th year, ignoring every team pratfall or franchise indignity. “If it does come out to be true, I would like to reach out, just from a personal standpoint, to offer some help,” he said. “You don’t want to see a guy ruin his career, or his life.”

Fletcher touched on a key aspect of recreational drug testing — if you keep failing, even in the face of $1.85 million in lost pay for Williams and bad publicity for Davis as he goes for a new contract, maybe you aren’t just irresponsible but need help.

Strictly in a football sense, the Redskins need plenty of help. After a hard-fought first three quarters, they led 16-13 in the fourth quarter, then fell apart, allowing 21 fourth-quarter points. Those three scores were virtually uncontested by a defense that has been the Redskins’ relative strength.

Santonio Holmes beat cornerback Josh Wilson so badly with a slant-and-go move that the Jet was open by five yards at the flag for an easy score and a 20-16 Jets lead. On the final two New York touchdowns, one after a Rex Grossman sack-and-fumble at the Washington 9-yard line, New York’s Shonn Greene plowed into the line where there appeared to be no hole. Both times, he burst out of the scrum, somehow virtually untouched, for scoring runs of nine and 25 yards.

“We had ’em right where we wanted ’em. I know, a cliché. But we thought we had ’em figured out. Then 21 [fourth-quarter ] points, that’s tough,” DeAngelo Hall said. Asked about the Williams-Davis reports, Hall said: “Some how, some way, we’re going to have to make it happen. To not have those guys — we’re better with them — but the sun will rise.”

Sometimes, the Redskins find so many new and amazing ways to embarrass or defeat themselves that the franchise seems to exist on two planes: as perennially poor football and bleak depressing theater. But it’s also easy to exaggerate every aspect of a sport that is played, and lived, under a magnifying glass.

“I don’t know what is going on with them,” Sellers said, “but Trent and Fred are both good guys.”

Given their talent, they’ll probably have years to prove it. But, most likely, starting next year.