Playing a pot dealer on TV, you assume Justin Kirk must frequently get asked his opinion on the social and political issues of the marijuana debate.

Well, not really...

“Oh it comes up,” laughs Kirk, who plays Andy Botwin on Weeds, which begins its fifth season on Showcase on Sunday.

“But the discussion goes more like — hey man, wanna smoke? Yes, I’ll smoke with you.”

Not that the quirky Weeds takes its title topic completely lightly. The show — which focuses on the misadventures of suburban mom-turned-dealer Nancy (Mary-Louise Parker) and her extended family — never quite gets away from the darker ramifications of the dope business.

Though its central characters are pretty likable, their experiences in the weed business are not always positive.

“Well, it’s not a public service announcement,” says Kirk who, besides Weeds, is best known for his work on the epic play-turned-miniseries Angels In America.

“So there’s no real position (on marijuana). I think when you start with my character and Kevin Nealon (as perennially-wasted neighbor Doug Wilson), how positive can it be? But it’s a great place to start off from.”

Kirk says the new season will take the show on a much more dangerous path as a pregnant Nancy finds herself involved with ruthless Tijuana mayor/drug lord Reyes (Demian Bichir), who also happens to be the father of her child. Reyes can’t quite decide if, or when, he should kill Nancy.

“We’re going way beyond where we’ve been. We’re going from selling dime bags to getting involved with a very dangerous drug kingpin.”

• The fifth season of Weeds begins Sunday night on Showcase