‘The Diplomat’ Review: Keri Russell’s New Assignment

The no-nonsense Kate Wyler ( Keri Russell ) is a longtime, behind-the-scenes Mideast troubleshooter who is about to take an ambassadorship in Kabul, where her expertise regarding Afghanistan will be invaluable. At the last minute, she is reassigned and made ambassador to the U.K.—“a Tiffany appointment” that Kate doesn’t want and in which the barely kempt operative’s aversion to ceremonial froufrou will be on constant display.

So far, a conventional fish-out-of-water construct. This viewer has no idea whether the world according to “The Diplomat” is the least bit plausible, although it makes sense. And will probably confirm a lot of suspicions people have about professional diplomacy—and politics, given that the machinations behind Kate’s upended career track are explained in a most believably cynical manner: The serving vice president—a woman—is about to resign over a financial scandal, and the handlers of the aging, hawkish and irascible President Rayburn (a likably churlish Michael McKean ) need someone with the necessary credentials to convince him of some unvarnished political truth. Also, to be a viable vice president. In the Court of St. James’s, Kate’s mettle will be tested.

Ms. Russell is a rather splendid Kate Wyler, a woman operating at a breathtaking intellectual pace but not one out of place among the mostly well-intentioned schemers at the top of the U.K. pile of intelligence officers, politicians, militarists and ministers. Her appointment raises eyebrows, and ire, but she wins people over, including the few who understand she’s being vetted for vice president. She is keenly aware she has been yanked out of the arena she knows, and where she thought she could do some good—salvaging “a shred” of what we spent “2,400 lives trying to accomplish.” That she is being examined as vice presidential timber is something about which she has no clue. Her husband, however, knows all.

This is only a minor exaggeration: Hal Wyler (a first-rate, revelatory Rufus Sewell ) is another State Department lifer, who lost his own job under the Rayburn administration for calling Secretary of State Ganon (Miguel Sandoval) a “war criminal.” Hal is a political insider who knows every back channel in international diplomacy, but doesn’t know when to step away, or shut up: He revels in global gamesmanship exactly the way Kate doesn’t, and the chemistry between them, while sexually alive, is unstable. Likewise, Hal’s ego, the master diplomat having found himself in London as the plus-one to his wife. Upon being given an introductory tour of the ambassador’s residence, Winfield House, Kate checks the sheets in the guest room. Meaning: The Wylers don’t sleep together. And a divorcée may not be as promising a candidate as the Rayburn people are looking for.

Hal and Kate are not Nick and Nora, or Mr. and Mrs. Smith, or Homer and Marge, though they can be very funny, the humor being rooted in consternation—hers, mostly, caused by her husband’s incurable habit of ignoring protocol and never telling her what he has done, ostensibly on her behalf. Like floating her as a possible VP. The central crisis in what would seem to be only the first of several seasons of “The Diplomat” is the bombing of a British warship, the immediate suspect being Iran. Cooler heads—Kate’s being the coolest of all (Ms. Russell is magnetic) and Hal’s being the savviest—have to ice down the feverish leaders who surround them, including Ganon, Rayburn, Prime Minister Nicol Trowbridge ( Rory Kinnear ) and, to a lesser degree, Austin Dennison ( David Gyasi ), the U.K. foreign secretary, who seems drawn to Kate, which is just shocking.

The intricacies of the plotting are ingenious, the pace brisk and the binge-ability factor high in what is a sophisticated show with a sterling cast that includes Ali Ahn (“Raising Dion”) as CIA station chief Eidra Park and Ato Essandoh as Stuart Hayford, Kate’s deputy minister. Like Eidra, Stuart is an immediate convert to the cause of Kate. As all of us will be.

—Mr. Anderson is the Journal’s TV critic.