The long and the short of TV series

American broadcast network television is a business whose traditional definition of perfect success -- a show that runs forever -- guarantees endemic failure. Failure here is defined not as a failure of nerve, vision, artistry or craft, which any program may or may not suffer to various degrees, but as a failure to perform -- to deliver the numbers that guarantee a full 22-episode season, and then another, and so on. It is therefore an anxious medium.

We have a tendency in this country to confuse a long life with a worthwhile one. It happens that good shows can sometimes run a long time, and it also often happens that good shows run past the point where they are no longer quite as good, especially if they are still making money. When the creators of a still-successful show take it off the air, as was famously the case with “Seinfeld,” to protect the legacy, it is seen industrially as whimsical and foolish, if not dangerous and deranged. There are series running now that could heed that example. But more is always better in commercial TV.

Nevertheless, the idea that a television series has to occupy a lot of temporal real estate to matter -- an idea shared by many people who watch television as well as people who make it -- began slowly to change about a decade ago, around the time “The Sopranos” came to town.

The success of that show changed many things in TV -- it opened the way toward darker themes and anti- heroes and made the medium attractive to writers and actors who had previously thought it second-rate. But just as significant is the fact that it did this in a season only 13 episodes long. It validated the short run -- what might be called the budget-minded British model. (A season of the original BBC “The Office” is less than a third as long as NBC’s American version.)

Because it’s cheaper to produce, the short-season model lets more networks into the game -- not just fairly flush premium cable networks, like HBO and Showtime, that have long used original series as subscriber bait, but, increasingly, humbler basic-cable networks that had previously just amalgamated reruns, old movies and various flavors of reality shows into the semblance of a brand.

AMC and TNT and USA, Syfy and FX, A&E, the Disney Channel and Nickelodeon, Spike and IFC, Lifetime, Comedy Central, Nickelodeon, BET all have taken a crack at original drama or comedy. (The big broadcast networks have yet to embrace a shorter season, with the exception of reality shows, except by cancellation.)

“Weeds,” “The Closer,” “Deadwood,” " Curb Your Enthusiasm,” " Battlestar Galactica,” “Brotherhood,” “Damages,” “Rescue Me,” “Sons of Anarchy,” “Burn Notice,” “Dexter,” “The Shield,” " Californication,” “The Riches,” “Somebodies,” “John From Cincinnati,” “Flight of the Conchords,” “Nurse Jackie,” “Drop Dead Diva,” “Army Wives” -- most of these range, or ranged, between eight and 13 episodes a season. Most only happened because the stakes were lower.

I haven’t liked all of them, but their diversity strengthens the gene pool; lower financial risk allows greater creative risk.

There is a kind of existential difference between a show that’s canceled after six or nine or 12 episodes because of low ratings and one designed to run only six or nine or 12 episodes in the first place, however many people watch it. The first is deemed a failure; the second, whether it is any good or not, gets to say its piece; if it fails, it is a failure of art. That strikes me as the healthier way to do things.

Shorter seasons can mean better focus and less filler; that the season is usually ordered whole also means that stories can be built over time.

This is seen nowhere better than with AMC’s Emmy-dominating “Mad Men”: Even with a large cast of characters, it can seem that nothing is happening on this show. The recently concluded third season in particular was a study in refusal and reticence, indecision and impotence. And then the crises come, steps are taken, and in the final episodes you see how the strands have been brought together, and how carefully the bow has been strung.

Next to the old 22-episode model -- fewer than the 30-plus episodes that made a television season through the 1960s -- the 13 episodes that make a season of “Mad Men” begin to seem like a roadster compared to a Humvee, efficient and economical where the other is unnecessarily large and resource-hogging. And if for 39 weeks out of the year there are no new episodes of “Mad Men,” that does not seem like a prob- lem to me. There is only so much television a person can watch.