Perhaps the best thing about The Good Fight - a spin-off of acclaimed legal drama The Good Wife - is its approach to the thorny issue of representation.

Diane Lockhart (Christine Baranski) is now working at an African-American firm. Her protege Maia Rindell (Rose Leslie) is gay. Straight white men are the minority.

Usually, this is where it ends. Producers make their casts more heterogeneous - often at the urging of viewers - and wait to be applauded. Diverse TV role models, it is assumed, deliver "trickle down" rewards to society. Their mere portrayal chips away at prejudice and counters discrimination.

As The Good Fight illustrates, the reality is more complex. Yes, Maia admires Diane; a wily and intelligent lawyer who has overcome her fair share of sexism. But their relationship isn't just a happy accident. Both belong to a wealthy liberal elite; indeed, Diane is Maia's godmother. Although their personal struggles are placed in a broader context, they are not universalised.

It's the same for the show's African-American lawyers, who face challenges their white peers do not - while also enjoying the advantages of wealth.

In the second episode, Maia and Lucca Quinn (Cush Jumbo) participate in a free legal consultation; part of a retainer agreement with a union client. There are plenty of worthy cases, and they take one on.

As for everyone else? Bad luck. While their cases are equally worthy, they miss out on pro bono assistance from a major firm. How many will be pressured into a plea bargain? How many will be crushed by their opponent's expensive lawyers? After all, "justice" has a funny way of happening to those who can afford it - and eluding those who can't.

Likewise, Diane grapples with her defence of police officers accused of brutality. When Maia questions if they are on the "right" side, Diane argues they are on a "necessary" side. In principle, this is true. But Diane didn't select this case on merit. Chicago's police department is one of her biggest (and most lucrative) clients.

Characters suffering economic hardship do not magically benefit from their interactions with inspiring women or powerful black lawyers. Their fates tend to be determined by the vagaries of politics and the law (at least to a greater extent than the rich).

Mercifully, none of this manifests as heavy-handed moralising.

"There has to be drama," Jumbo says. "The audience has to care about the characters. The politics, the voices of females, the race elements: they're all wrapped up in that. But you don't stand a chance if you don't have a good story."

As with its predecessor, The Good Fight is technically a "legal drama". But such a term can imply formulaic plots and cardboard characters. It's better described as a "premium drama" that uses legal storylines as a hook - and a device to explore bigger social and economic issues.

"It's an African-American firm, but it doesn't mean we have an 'issue' about racism every week," Jumbo says. "You don't just see black people pop up when a crime is being committed, or a drug deal is happening, or they need an exotic sexpot. There are good lawyers and bad lawyers. Annoying lawyers and arsehole lawyers. And they can be black, too."

Of course, Diane was a lead character in all seven seasons of The Good Wife, while Lucca appeared in its final year. Unlike its predecessor, The Good Fight was made for CBS' subscription streaming service. Jumbo believes this allows more creative freedom for Robert and Michelle King, the series' creators and writers.

"When a show is online, or on cable, a lot of focus can be thrown onto nudity and swearing," she says. "But for the Kings, it's more about being politically open [with their storylines]."

In part, their success is due to the series' quick turnaround. Instead of writing months in advance, the Kings map out a long-term narrative arc while reflecting current events.

"They create these great characters and run with them," Jumbo says. "That's why I love the show and why the audience keeps coming back."

WHAT: The Good Fight
WHEN: SBS on Demand, all episodes available for streaming