Is there life after death in Venice? The makers of “Imagining Argentina” are praying there is.

Since Christopher Hampton‘s movie was slaughtered by the media at the Venice Film Festival a few weeks ago, its star Emma Thompson has been canvassing support from potential allies in the hope of rescuing the film from oblivion.

“You can’t fight the bad reviews, you can’t rush around saying they are wrong,” she says. “That doesn’t work. What you have to do is find opinion and influence in other areas that are important.”

She has arranged screenings of the movie — a political thriller financed by Myriad Pictures about the disappearance of tens of thousands of people under Argentina’s military dictatorship in the 1970s — for the likes of BBC foreign correspondent Feargal Keane and human rights orgs Amnesty Intl. and the Medical Foundation.

In “Imagining Argentina,” Thompson plays a journalist who is kidnapped and tortured by the military regime. Antonio Banderas portrays her husband, a children’s entertainer who embarks on a quest to find her, aided by some previously unsuspected psychic powers.

This uncomfortable blend of graphic brutality with dreamy magic realism drew jeers from the Venice crix. The movie has already entered Lido myth as one of the worst received in the event’s history. In truth, it got a six-minute ovation at the subsequent public screening, but by then the damage had been done.

“What upset me about what happened at Venice was not the bad press, but that the subject of the film itself had been overlooked, and so we’d somehow led to the betrayal of the disappeared all over again,” Thompson says.

“Torture and occluded secret histories are very difficult to get at. I’m interested in the umbrage taken at mixing that kind of brutal reality with visions, portents, symbols. But the more I consider it, the more I think it’s one of the only ways you can do it.

“I really haven’t slept since, lying awake thinking about the intellectual ramifications of this subject,” she confesses. “We’ve got to try it again and again until we get it right.”

Amnesty is planning to host its own screenings around the world for activists, politicians, celebrities and journalists. Bonnie Abaunza of the org’s U.S. arm comments, “The fact that magic realism is interspersed throughout the film as a means of artistic expression should not diminish its ultimate message of hope and love in the face of such brutality.”

But it’s Thompson’s willingness to stand up in the face of an overwhelmingly negative press and fight for a movie she so passionately believes in that distribs see as the pic’s last best chance to reach any kind of wider audience.

“There’s a single-word answer to how we turn this around — Emma,” says David Livingstone, president of marketing at Universal Pictures Intl., which is releasing the movie via UIP in the key territories of Spain, the U.K. and Latin America.

“Only somebody of her visibility, articulating why she wanted to make this film, to deal with this subject matter, with intense passion, humor, style and substance, might persuade people to see this film.”

The odds are clearly stacked against it. The pic has already flopped in Italy, and it remains unsold in France and Germany. Its U.S. release via Focus is hanging in the balance. Much, perhaps all, now hinges on the Spanish release in December, where the combination of Banderas and Thompson (who is much loved by the Spanish press), plus the Argentine setting, would normally be a big draw.

The whole experience has made Thompson more determined than ever to crack her own screenplay, seven years in the writing, about the murder of Chilean troubadour Victor Jara during General Augusto Pinochet‘s U.S.-backed coup in 1973.

Not everything she touches is quite so earnest. After “Imagining Argentina,” her first big film role in four years, she appears in Richard Curtis‘ frothy romantic comedy “Love Actually.” Her next movie, which she wrote and will star in, is “Nanny McPhee,” directed by Kirk Jones for Working Title; it’s a kind of modern-day “Mary Poppins.”

But for Thompson, who has never separated the personal from the political, such range is not a stretch at all. “Nanny McPhee,” she says, “will have everything I believe in about how people should behave, struggling with what it is to be human. And that goes for ‘Love Actually’ as well. I’m not into doing agitprop. What appealed to me about ‘Imagining Argentina’ was its imaginative approach.”