In a film-making career spanning almost 40 years, Oliver Stone has turned political controversy in America into an art form. He has upset financiers with his caustic portrayal of Wall Street; conservatives with his depiction of Fidel Castro, Hugo Chávez and George Bush; and Democrats with his conspiracy theories about the assassination of John F Kennedy.

All of which may come to look like a tea party – of the social as opposed to right-wing protest variety – when his next big venture hits the screens.

Stone announced yesterday that a 10-hour crash course in the history of the 20th century he is putting together for American TV is designed as an antidote to the inaccuracies and biases he believes exist in the conventional historical narrative dished out in American schools and mainstream media. The title alone gives an inkling of what lies ahead: Oliver Stone's Secret History of America.

The thrice-Oscar winning director gave a further glimpse into his thinking at a gathering of TV critics in Pasadena on Saturday, when he didn't so much open up a can of worms as unleash an entire supermarket shelf-load. He began by startling the panel by bringing up the H word.

"Hitler is an easy scapegoat throughout history and it's been used cheaply," he said. Then he mentioned the S word. "Stalin has a complete other story. Not to paint him as a hero, but to tell a more factual representation. He fought the German war machine more than any person."

Then he went on to mention two M words – Chairman Mao and Joseph McCarthy, architect of the 1950s anti-communist purges in Washington, and the T word – Harry Truman's dropping of the atom bomb in 1945.

Of the many potential storms that could be brewing over his Secret History, which will be broadcast by the cable channel Showtime later this year, Hitler promises to be the most incendiary. Stone told the Television Critics Association that "we can't judge people as only 'bad' or 'good'. [Hitler] is the product of a series of actions. It's cause and effect. People in America don't know the connection between WWI and WWII."

The implication that Stone is seeking to put forward a good side of the German dictator hitherto not seen by Americans is, even by Stone's own accomplished record of stirring up stinks, pretty radical.

The comment inspired Stone's collaborator on his Secret History, Peter Kuznick, a history professor at the Washington-based American University, to tell the audience of television critics and, in an apparent damage-limitation exercise: "He's not saying we're going to come out with a more positive view of Hitler. But we're going to describe him as a historical phenomenon."

Even so, such a relativist approach to Hitler as a product of his time as much as an individual embodiment of evil is likely to prove hot material. Stone said he would similarly put Stalin "in context". "I've been able to walk in Stalin's shoes and Hitler's shoes, to understand their point of view. You cannot approach history unless you have empathy for the person you may hate."

Within hours of the comments being made, they had begun, in the predictable pattern of such things, to effervesce on the internet like yeast in dough.

A blogger by the pen name Orphia Nay summed up the billowing emotion: "Ohhhhhh, this is not going to end well," she wrote. Others were less temperate. "Again, another 'blame America first' person. If he/they hate it, just leave it. We'll all have a party and help you pack. You won't even have a full body scan."

Say what you will about Stone, he can't be accused of opting for the easy life. His 2006 film on 9/11, World Trade Center, was both critically acclaimed and a box office hit, with an appeal to all political persuasions. Next he bounced back with a sharp portrait of George Bush in W. Then he made South of the Border, his glowing portrayal of Chávez as champion of the poor which premiered at the Venice film festival in September where Stone appeared with Chávez on his arm. His Wall Street 2, with Michael Douglas reprising Gordon Gekko, is in post-production; it's a fair bet that the money men will come off no better this time than they did the last.

Now his Secret History. "Obviously, Rush Limbaugh is not going to like this history," Stone told the TV critics, which may go down as one of the great understatements of all time.

Courting controversy

• JFK (1990) Caused a furore by asserting that JF Kennedy's vice-president and successor, Lyndon B Johnson, was involved in the president's assassination in Dallas in 1963 along with CIA agents and anti-Castro exiles. One critic called it "a monstrous charade''

• Natural Born Killers (1994) A savage portrayal of a young couple's killing spree. Intended as a satire on the media's obsession with violence, the film was subsequently linked with a series of copycat murders

• Comandante (2003) A US network postponed Stone's documentary on Fidel Castro, following a crackdown on dissidents by the Cuban leader. Stone spent three days with him n 2002 to make the film but was accused of being too sympathetic

• W (2008) Even before release, Stone's portrayal of former president George W Bush had rightwing columnists and bloggers condemning it as a vicious smear although the New York Times was among those who thought "he (Stone) goes easier on Mr. Bush on screen than some of his off-screen remarks suggest

Holly Bentley