Like last week's "The Strategy," Mad Men's midseason finale "Waterloo" was so rich and satisfying that it could have been the series finale. I'm so relieved that it's not. With its ultimate end in sight, Mad Men has been firing on all cylinders, and "Waterloo" is a textbook example of this show at its very best.

Now that Community is off the air, there is no show that rivals Mad Men for its inventiveness and elasticity. When people talk about TV's most shocking moments, they generally refer to something like Game of Thrones' Red Wedding. But that infamous scene — effective as it was — was well within the scope of what viewers have been trained to expect from Game of Thrones, which has built much of its cultural cache on the premise that none of its heroes are safe.

By contrast, the big death in Mad Men's seventh season happened off-camera. Rest in peace, Bert Cooper. The loss of Sterling Cooper's oldest (and often wisest) employee is a sad one, but it also marks the fitting end of an era for the firm as it looks to a future under the umbrella of McCann Erickson.

Fortunately, Mad Men found the perfect way to give Robert Morse one last swan song as Cooper. I don't think anyone predicted that Mad Men's midseason finale would end with the ghost of Bert Cooper performing a whimsical soft-sock version of "The Best Things in Life Are Free," but Mad Men is so consistently unpredictable that I hardly batted an eye at the episode's funny, bizarre, poignant final scene. Mad Men has dabbled in the supernatural before — Don's hallucinations of his father, or his vision of Anna Draper in "The Suitcase" — but the series has rarely been this playful, and the results were deeply rewarding.

As memorable as the ending was, much of "Waterloo" was vintage Mad Men: terrific performances, beautiful speeches, and some of the most gorgeous cinematography, set design, and costuming available on television. Mad Men is showing its age, and I mean that as the highest compliment. Whether or not you believe that we're in the midst of the fabled "golden age of television," the medium is changing, and Mad Men's ultimate finale next year will be a bittersweet one, because no series has stepped up to take its place. Mad Men is the last member of the old guard that's still standing, but it's not standing still; seven years and 85 episodes after its original premiere, it's still finding new ways to be innovative and surprising.

Given its unfailing commitment to expanding its depth and scope, it's amazing that Mad Men holds together so well. If you had to boil the series down to a single question, it would be "Who is Don Draper?" — and virtually every character who appears in "Waterloo" has an opinion on the subject. "I'm starting to think of him as an old, bad boyfriend. Someone a teenage anthropologist would marry," says Betty. "You're just a bully and a drunk. A football player in a suit," says Cutler. Don is "a very sensitive piece of horseflesh," says Pete. He's "a pain in the ass," says Cooper.

But for all the judgment he's facing, Don Draper gets to determine who Don Draper is, and he does it with uncharacteristic selflessness and grace. Don clearly didn't see his split from Megan coming, but once he realizes the sad truth that Megan can't bring herself to say, he doesn't handle it with the bile he once spewed at Betty; instead, he promises Megan all of the resources he can offer and allows their marriage to come to a quiet end. Later, he makes a professional sacrifice when he tells Peggy to deliver the Burger Chef pitch, voluntarily giving up his last chance to make himself irreplaceable at Sterling Cooper so he can give his protégé the chance she earned. His trust is well-placed; Peggy's pitch is so good that she arguably out-Drapers the actual Don Draper, landing the account and delivering a powerful tribute to the idea of shared experiences.

And then, shortly after Apollo 11 touches down on the moon, Cooper dies, and everything changes. Like Don, we hear many opinions about who Bert Cooper really was. "A giant," says Cutler. "A wonderful man," says Joan. But as with Don, the actions are far more important than the words. Jim Cutler, who never really knew or cared about Bert Cooper, suggests reading Walt Whitman's "O Captain! My Captain" to the office — perhaps the Platonic ideal of a phoned-in eulogy.

Fortunately, Roger Sterling finds a far more fitting way to pay tribute to his lifelong mentor: a series of savvy professional maneuvers that ensure the future of Sterling Cooper while achieving everything he personally wants. (In the end, even Cutler can't resist the plan he devises.) In their last conversation, Cooper insisted that Roger wasn't strong enough to lead: "I'm a leader, and a leader is loyal to his team." But whether he actually meant that, or merely knew the right way to motivate Roger, the effect was the same. By the end of "Waterloo," Roger ensures that every partner at Sterling Cooper stands to gain over a million dollars when they agree to become a subsidiary of McCann Erickson — but they didn't give up any employees or clients, and they retain complete autonomy to act in their own interests. Cooper (and Ayn Rand) would undoubtedly be impressed.

The episode ends with a certain kind of order restored: the powerful will remain powerful, and Don will remain at the firm he originally founded for at least the duration of his five-year contract. But make no mistake: with just seven episodes left, Mad Men could take its story almost anywhere. The series could pick up one week after "Waterloo," or six months, or five years, or 20.

But wherever we rejoin the narrative, there's one central question left to be answered: whether or not Don Draper can ever be redeemed. "No man has ever come back from leave," says Cooper, ominously. "Even Napoleon." It's a dark prophecy — but it's also a prophecy that he personally disproves at the end of the episode, when he marks the multimillion deal by returning from the grave and reminding Don that the best things in life are free.

It doesn't matter if it actually happened; it means something to Don, who nearly breaks into tears at the vision of Cooper delivering one last lesson as he cheerily dances off to his death. Once again, Don has been handed a clean slate to rebuild his life again — and the last time he had that opportunity, he created "Don Draper." What will he do with it this time?

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