‘The Diplomat’ season 4 review: Netflix’s best drama delivers its best season yet

Netflix's “The Diplomat” has somehow gotten better with every season, which itself is a plot twist when you consider how more Netflix shows fare as they age. It could've just maintained the momentum after three seasons of political intrigue, marital warfare and Keri Russell looking increasingly disheveled. Instead, season 4 doubles down on what has always made the show so much fun: putting brilliant, deeply complicated people in rooms together and watching them try to outmaneuver one another while barely holding their personal lives together.

I've now watched all eight episodes of season 4, and I can say that "The Diplomat" remains one of Netflix's best dramas — if not the very best. The plotting is intricate without becoming incomprehensible, the stakes continue to escalate and the show has added two major weapons to its already formidable arsenal: Allison Janney and Bradley Whitford. Their arrival as President Grace Penn and First Gentleman Todd Penn was already a highlight of season 3, but season 4 brings them much further into the action, and the results are fantastic. Janney, Whitford, Russell and Rufus Sewell have the kind of chemistry where they could just read an encyclopedia together and it'd be high theater.

So what makes "The Diplomat" season 4 work so well? It's not just the increasingly high-stakes geopolitical maneuvering, but the complicated personal relationships that make every backroom deal feel like a potential marriage-ending argument. And this season has plenty of both.

‘The Diplomat’ keeps the political thrills coming

Season 4 picks up the complicated threads left dangling at the end of season 3, particularly the fallout from Grace and Hal's secret operation involving Russia's Poseidon weapon. From there, things get considerably more dangerous, with Kate caught between competing political agendas and her own increasingly complicated relationship with Hal.

What I've always appreciated about “The Diplomat” is that the plot is complex without feeling like you need to do homework. Even with all of the covert operations, shifting alliances, international brinkmanship and diplomatic schemes, there's a clear and comprehensible throughline connecting this season to everything that came before it.

This time around, a new threat puts President Grace Penn on an increasingly hawkish footing, increasing the pressure on everyone caught in her orbit. Meanwhile, First Gentleman Todd Penn becomes more involved in the geopolitical game, complicating an already precarious balance of power. His influence on Grace adds another unpredictable element to the mix, especially as he and Kate find themselves navigating an uneasy alliance.

The one slight weakness is that Russia continues to function more as a looming boogeyman than an actual presence. The threat is certainly there, and the geopolitical stakes are enormous, but the show is more interested in what its American and British characters think Russia might do than in showing us much of Russia itself. That's not necessarily a big problem, but it does make some of the consequences feel a bit abstract.

Fortunately, “The Diplomat” has never really depended on its geopolitical machinations alone. The political crises are the engine, but the relationships are the reason you keep watching

The relationships are what make ‘The Diplomat’ so addictive

The real heart of season 4 is Kate and Hal's marriage, which remains an absolute disaster in the most compelling possible way. Their relationship is so tangled, competitive and electric that it's almost impossible to look away. Kate is still not sure if their marriage is worth saving, while Hal has a remarkable ability to make every situation approximately 487 times more infuriating.

I do miss Kate's flirtation with Austin Denison, though. With David Gyasi's British foreign secretary spending much of this season offscreen, that particular spark is largely absent. And I'm not nearly as invested in Kate's fling with Callum Ellis (Aidan Turner). Still, the show has always been at its best when Kate and Hal are orbiting one another, whether they're fighting, flirting or trying to save the free world.

Whitford gets considerably more to do this season, and his scenes with Russell add very interesting layers to the mix. Janney continues to give an Emmy-worthy performance as Grace, and I love the interplay between her and Whitford, as well as Russell and Sewell (and all permutations of the quartet).

Then there's Stuart (Ato Essandoh) and Eidra (Ali Ahn), whose relationship continues to be one of my favorites on the show. Things escalate between them in season 4, and somehow their already unusual dynamic becomes even more delightfully weird and banter-iffic.

And then Jodie Whittaker arrives as a high-ranking British politician, and she is terrific. Her rapport with Russell is immediate, giving Kate another formidable personality to spar with.

Verdict: 'The Diplomat' remains one of the best shows on TV

Four seasons in, “The Diplomat” is somehow getting better, with intricate political plotting and messy relationships that keep you hooked. Keri Russell, Rufus Sewell, Allison Janney and Bradley Whitford are firing on all cylinders, making this another must-watch season despite a few minor missteps.

What really sets the show apart, though, is how effortlessly it balances international intrigue with the messy business of being married to someone who might just be your biggest rival. The plot will keep you hitting “Next Episode,” but it's the characters who make you glad you did.

"The Diplomat" season 4 is streaming now on Netflix