Was Ronald Reagan a kindhearted conservative who remade government and merits his standing as a beloved icon of the Republican Party? Or was he a glorified actor who won election with a coded racist appeal to white voters, setting the stage for the rise of President Trump?

That debate has long absorbed Reagan historians and biographers, particularly these days as Reagan’s legacy seems ever more gauzy when held up against these past four years of the just-defeated president.

And it is now being tackled in “The Reagans,” a four-part documentary on Ronald and Nancy Reagan premiering Sunday on Showtime. It is the work of Matt Tyrnauer, a documentarian whose past subjects have included Roy Cohn, the fashion designer Valentino and Studio 54.

Tyrnauer grew up in Los Angeles when Reagan was governor of California. As a boy being driven to school by his father, he sat in traffic as the motorcade taking the newly elected president from his home in the Pacific Palisades to a postelection news conference in Century City sped down Sunset Boulevard.

From the second installment of “The Reagans,” it is clear where Tyrnauer, who began his career as a junior aide in Democratic politics before moving into magazine writing and directing documentaries, comes down on Reagan’s place in the nation’s fraught history of race and politics. The episode opens with 40-year-old footage of Reagan in Mississippi, affirming his support for “states’ rights” at a county fair filled with white voters.