“House of Cards” returns, and in terms of classy actors in a high-stakes setting, it’s solidly entertaining. Still, the series that set Netflix on the path to programming prestige also feels played out, as if it should have retired without seeking a third term. Kevin Spacey and Robin Wright remain splendid as the central couple, but with their quest for power having succeeded, series architect Beau Willimon seems forced to resort to unconvincing contortions to maintain the drama. Even then, the first half of Season 3 feels flimsy, having essentially morphed into an inordinately ruthless version of “The West Wing.”

Those caught up on the first two seasons will know by now that Spacey’s Frank Underwood wheedled and schemed his way from Congress to the vice presidency to the Oval Office, knocking down a surprisingly ineffective assortment of barriers to his ascent. Indeed, a lingering criticism of the show is that in a town driven by deception, spin and the quest for power, Frank has lacked a genuinely worthy adversary, with his opponents appearing consistently mismatched in the elaborate chess game he’s been playing.

It’s a misgiving that’s exacerbated by placing both of Underwood’s hands so firmly on the levers of power. Being President, after all, comes with a lot of firepower, even if he faces a hostile Congress and the lingering threat of exposure for past transgressions.

The season opens promisingly enough, with the new prez grudgingly engaging in a ceremonial moment that, he sneers, “makes me seem more human.” From there, “Cards” begins rolling along various tracks, with diverse crises arising, and a number of not-created-equal subplots that shouldn’t be spoiled — one involving the first lady (Wright), who desires to be more than just a photo-op figurehead.

To his credit, Willimon remains a shrewd observer of modern politics in many respects, and it’s no accident that “House of Cards” frequently mirrors reality, and vice versa — from strained relations with Russia’s authoritarian leader to Underwood seeking to champion a jobs program basically lifted out of the movie “Dave” that’s similar to President Obama’s desire to use federal spending on infrastructure to bolster the economy.

At the same time, Underwood’s plans to circumvent Congress are a bit too transparent early on, and the first lady’s plot is well played but politically hard to swallow, its homage to the Clintons notwithstanding. Nor do Underwood’s occasional pangs of conscience feel in completely keeping with the character’s win-at-all-costs nature.

“House of Cards” is still a valuable franchise for Netflix, in ways both subtle and obvious. The political setting, for example, ensures a regular string of cameos by media figures, from MSNBC and CNN anchors to Stephen Colbert, creating what amounts to a multiplier effect in terms of coverage and credibility.

The flaws, however, have always kept the show from being fully deserving of all the praise and attention showered upon it, and while it remains considerably fun to watch (or binge), its shortcomings look somewhat magnified in this third season. Yes, this handsome political drama effectively established Netflix as a home for premium-quality programs, and it’s simultaneously one of this nascent medium’s best programs, but it’s also a franchise whose legacy might be tarnished in part by not quitting while it was ahead.

Then again, in that respect at least “House of Cards” is merely guilty, in TV terms, of being a little too human.