In a ‘Nightline’ interview the day J.K. Rowling’s already best-selling adult novel, “The Casual Vacancy,’’ was released, the author of the Harry Potter series wasn’t shy about stirring a leaky cauldron of class politics.

Author J.K. Rowling (Paul Hackett/Reuters)

Once a financially strapped single mom, Rowling penned her way to literary fame and became a billionaire in the process. But she says she doesn’t relate to the feeling of many American conservatives that everything they have they can look at and feel, “We built it.”

“I know that in your country at the moment, [you have] this ‘We built it’ catch phrase,” Rowling told Cynthia McFadden, referring to Republican pushback against President Obama’s more communitarian view that, as in the Bruce Springsteen song that played after the president’s speech at the Democratic National Convention, “We take care of our own.’’

(What Obama said: “If you’ve got a business — you didn’t build that. Somebody else made that happen.” What he says he meant: We all rely on one another, and benefit from public works in some way. What his critics heard: From government comes all good things.)

Rowling’s own feeling, she said, is that it was Britain’s government services that allowed all her industry to pay off.

“I worked extremely hard… I take credit for the work. But I received a free education. I received free health care… I’m unapologetic about saying this,” she added. “I had pneumonia when my daughter was under one year old. If we hadn’t had free health care in this country, God only knows what would have happened to either of us. I am proud of having done what I’ve done. Very proud. But. I do take issue – and this does go to the heart of this book, which is why I have to say it—with anyone who truly feels it’s a 100 percent down to them.”

In fact, wealth felt like an interloper at first, an intruder that interrupted the life Rowling knew.

“Honestly, the shift was so dramatic,” she tells McFadden. “I found it very disorientating. I felt guilty, strange, out of order. And now I feel a bit more grown up about it. And I think, no, I don’t feel guilty. I can do great stuff with this money.”

As she and her husband Neil Murray raise their family in Scotland, Rowling says their lessons to their children include discovering their gifts. “For us, finding out what you’re good at, and doing it to the best of your ability, is the route to self-respect,” she says. “And I would be, as my children well know, extremely disappointed, and I would feel that I had failed, if I turned out individuals who felt their contributions to society should be simply to consume.”

Rowling’s words won’t make the wealth wizards happy, needless to say — and already, she’s been criticized for peddling her political views.

According to journalist Daniel Greenfield in FrontPageMag, Rowling is the “British Elizabeth Warren.” The “shrill, left-wing screed,” otherwise known as Rowling’s “The Casual Vacancy,” apparently inspired Greenfield to give Rowling a name change and compare her to the Massachusetts Democrat.

The very adult-themed story, which has gotten mixed reviews, takes place in the imaginary Pagford, an English village at war with itself. Expect drugs, sex, along with marital, family and economic class disputes in this story.

The novel was No. 1 on Amazon before its release, but Rowling told McFadden, that she realizes “The Casual Vacancy” may not touch the pinnacles of the Harry Potter books. But having already sold 450 million books, no wonder she feels free to write what she wants — and say what she wants, too.

Judy Howard Ellis is a Dallas-based creative consultant for entrepreneurs and the author of “Fall of the Savior-King,” a fantasy novel inspired by the Book of Genesis. Follow her on Twitter: @JudyHowardEllis