Showtime making a killing on Sunday nights

Things have gotten so bad that Showtime is injecting these insecurities into its shows. There’s so much performance anxiety coursing through its series, you’d swear the entire lineup was being sponsored by Cialis.

If “Californication” (10:30 p.m. Mondays), which is fast becoming appointment television, weren’t enough — David Duchovny stars as a critically acclaimed novelist with writer’s block — “Dexter” (9 p.m. Sundays) and “Brotherhood” (10 p.m. Sundays) feature world-class killers no longer capable of finishing the job.

Dexter Morgan (Michael C. Hall) is a blood spatter expert for the Miami police by day and the city’s worst serial killer by night. Or its best, depending on whom you ask.

You see, Dexter lives by the code of Harry (James Remar), the cop who raised him from a very young age after his mother was butchered. For days, Dexter was locked in a cargo container with her corpse and a Tarantino-esque volume of blood. Thanks to that early trauma, as Hank Hill would say, that boy ain’t right.

Sensing this, Harry instilled in Dexter a very specific way of channeling his rage: killing only the worst of humanity. But lately, Dexter has had too much on his mind — “My life’s been all Jekyll and no Hyde,” he complains in one of his chillingly emotionless voiceovers — to get his murder on.

He’s being tailed around the clock by the ever-more-suspicious Doakes (Erik King), the sergeant he often works cases with, who’s as tough as your granddad’s toenails.

His underwater burial ground has been discovered, along with 18 corpses and counting, landing him the moniker the Bay Harbor Butcher.

FBI agent Frank Lundy (Keith Carradine) has brought the air, and the entourage, of a rock star to Miami as he sets out to find the Butcher and solve his latest unsolvable case.

And Dexter’s detective stepsister (Jennifer Carpenter) is on his trail, too, part of Lundy’s task force that also includes most of what passes for Dexter’s friends.

If he didn’t have an overwhelming need to kill before, he would have developed one after all this.

Thankfully, his adoring girlfriend (Julie Benz) has mistakenly become convinced that Dexter has a hard-core drug habit and demands that he enroll in a 12-step program. There, he meets his sexy sponsor (Jamie Murray), who seems to understand all of his darkest impulses, just so long as Dexter can remember to substitute “I shot up last night” for “I kidnapped a murderer, stripped him naked, bound him to a table and confronted him with his crimes before dismembering him.”

While Dexter’s problems are in his head, brutal gangster Michael Caffee’s (Jason Isaacs) problem, for the most part, is his head.

Michael was so severely beaten by a drunken Declan Giggs (Ethan Embry) in “Brotherhood’s” first season finale that he occasionally lapses into a catatonic state. Isaacs always has had a certain De Niro-like quality, but until now it’s been more from the Scorsese era than “Awakenings.”

As its name implies, “Brotherhood” is the story of Michael and his brother Tommy Caffee (Jason Clarke), the majority leader of the Rhode Island House of Representatives. Despite the wide gap in their popularity on “The Hill,” Providence’s deteriorating Irish community, the brothers really aren’t that different. It’s just that Tommy’s crimes — kickbacks, vote selling and the like — are a little more organized.

While the brothers are still front and center, Embry’s Declan gets a meatier story line than you’d expect for the fourth, and hopefully final, Rusty in the “Vacation” series.

Declan’s wife left him after the beating, and he’s deteriorated into a drinking, drugging, whoring mess. Adding to his misery, the only way he can keep his state police detective job is by bringing down his lifelong friends, the Caffees.

It would be easy to write off the Irish mob drama as “The McSopranos,” but the richly layered series offers a glimpse at life you don’t often see on TV. “Brotherhood” is so relentlessly working class, its characters would watch “Roseanne” with the same mix of awe and envy that other viewers — especially the ones who can pony up for the Showtime bill each month — would find in “Dynasty.”

Together, the dramas make for the darkest two-hour block on TV. One that’s so grim, you almost wish the pay channel would follow it with some lighter fare. Like unicorns or genocide.

But once you get past that, watching Showtime and its killers try to regain their swagger is still the best way I’ve found to spend a Sunday night.

Christopher Lawrence’s Life on the Couch column appears on Mondays. E-mail him at clawrence@reviewjournal.com.