Online retail giant Amazon jumped on the original Internet TV programming bandwagon Friday with a character-driven political sitcom created by the man behind the "Doonesbury" comic strip.

"Alpha House" stars John Goodman, Clark Johnson and Matt Malloy as old-school Republican senators sharing a Washington row house and facing re-election. Mark Consuelos co-stars as a cocky political upstart who moves in as their new roomie.

The first three episodes, including a well-received pilot that first went online in April, are free to all US viewers on Amazon Instant Video; subsequent episodes will need a subscription to Amazon's $79-a-year Prime option.

By kicking off with sitcoms -- the nerd-centric "Betas" premieres Wednesday -- Amazon is setting itself apart from online video rival Netflix, which favored hard-edge political drama for its original programming debut.

"We're in uncharted waters," Garry Trudeau, who took a sabbatical from the daily duty of drawing "Doonesbury" to focus on "Alpha House," told AFP in an email interview this week.

"No one is quite sure what success -- or failure -- looks like," Trudeau said. "As with Netflix and 'House of Cards,' our show will only be a hit if Amazon says it is."

Likely to guide Amazon's tastemakers are the comments that viewers are invited to leave online.

In lieu of dropping an entire season's episodes in one fell swoop, as Netflix did with its 13-episode "House of Cards," Amazon is releasing three episodes first, then one a week for the remainder of the season.

The idea is to get viewers to "chat about the shows and build up anticipation," said Roy Price, head of Amazon Studios, the film and TV development unit of the world's biggest online retailer.

"We're constantly experimenting and trying new things and we're eager to hear customers' feedback on this model," said Price in a statement earlier this month.

Amazon launched Amazon Studios in 2010 as an incubator for original programming. Since then, it's received more than 15,000 movie scripts and 3,600 series pilot scripts -- 24 of which have gone into development.

Trudeau, 65, who launched "Doonesbury" 43 years ago when Richard Nixon was president, said "Alpha House" was inspired by a 2007 New York Times feature about four real-life Democratic senators who share a two-bedroom house in the US capital.

For the show, "three of our characters are Republican senators who are facing primary challenges from far-right Tea Party opponents," he said, "so underlying all the fun is a very real existential threat to their careers."

Golden Globe winner and Coen Brothers favorite Goodman plays Gill John Biggs, a Republican senator from North Carolina with a deep southern drawl, a pet bloodhound and a hankering to somehow hang onto elected office.

Trudeau said the basic narrative structure of "Alpha House" is "quite similar" to his lampooning comic strip -- "several long-running, character-driven story arcs braided together with lighter riffs that resolve quickly."

He acknowledges he was reluctant at first to get involved with a web series: "The main misgiving I had concerned the platform itself... All I'd seen were 'webisodes,' underproduced, cheesy-looking YouTube videos."

In fact, so high are the production values on "Alpha House," which was shot on a New York sound stage, that some critics liken it to programming on long-established cable channels.

"Its look and feel and language are pure HBO/Showtime, though the party specificity is the sort of thing liable to keep it off 'regular' TV like HBO and Showtime," wrote Robert Lloyd in the Los Angeles Times.