Natalie Portman enters the screening room wearing black shoes, a black dress and a black cape. The effect is stylish, if sombre. She could be in mourning. Or maybe Darth Vader has lured her to the dark side after all.

The effect dissolves when she extends a hand, flashes a blinding smile and reveals a sizeable belly bump. She plonks down in the front row, taking the weight off her legs. Portman is seven months pregnant and taking the radiance business seriously. She looks great.

The actor is enjoying a collision of glad tidings. She has moved back to Los Angeles from Paris, is about to have a second child (her son, Aleph, was born in 2011) and is receiving rapturous reviews for her performance in Jackie. If the bookies are right, she might well top it all with an Oscar.

Hence the screening room. Earlier, a few dozen Academy members filed into this discreet Beverly Hills sanctum to watch the Jacqueline Kennedy biopic and hear why they should vote for Portman, as well as others who worked on the film. It’s one small front in the PR-campaign blitz that consumes Hollywood during awards season. Now they are gone, the screen is blank and the room is nearly empty.

Campaigning while heavily pregnant – you’re a trouper, I say. Portman laughs it off. “It’s all good. It’s not coal mining.” After a two-year sojourn in France, Portman, 35, seems happy to be back in LA. “Here is much more a place to make art. It’s just very inspiring light. A lot of freedom.”

Portman in Jackie. Photograph: Pablo Larrains/Twentieth Century Fox

Portman sips a herbal tea and holds court with grace and wariness, smiling often while weighing each word, with a guardedness that comes after decades in the public eye.

The solemn attire feels apt. Later in the day, there will be a joint funeral service for Carrie Fisher and her mother Debbie Reynolds, who died a day apart. In the Star Wars prequel trilogy, Portman played Princess Leia’s mother. Queen Padme Amidala was also, of course, missus to Anakin Skywalker before he became Darth Vader.

Portman is now also indelibly associated with the world’s most famous and enigmatic widow. Jackie, directed by Pablo Larraín, is an intimate portrait that swirls between John F Kennedy’s assassination and the grieving first lady making funeral arrangements a week later.

The termination of a progressive presidency, the nation bewildered and anxious, the future uncertain: resonant themes on the cusp of the Donald Trump era. “It certainly has taken on different meanings because of the context we’ve landed in, which was completely unexpected and unpredictable,” says Portman. “Noah Oppenheim, who wrote the script, has been saying that it shows our country has been through many difficult times, and we’ve managed to pull through and come out the other end of the tunnel.”

Portman, a vegan and activist for liberal causes, campaigned for Hillary Clinton in Pennsylvania. She warned in an October interview that a Trump presidency would be “catastrophic”, especially for women’s rights.

Now, with the casino owner moving into the White House, the actor is more circumspect, though still emphatic. “I don’t remember saying it would be a catastrophe but I do think it is a very upsetting moment because of the way he has spoken about women, about minorities, about immigrants. I don’t think that kind of discriminatory speech or behaviour is helpful to bringing people together in a positive way.”

She campaigned in what turned out to be a decisive swing state but, like many of us, fell for the polls and punditry which dismissed Trump’s chances. “I didn’t sense it myself, and that’s maybe part of the problem. We don’t interact enough with people from different political persuasions. People tend to hang out with others who think alike, and it makes you less aware.”

Given the controversy over artists performing at the president-elect’s inauguration, I ask if, in their shoes, she would do so. Portman bats it away. “I don’t think that’s really a likelihood as I’m not a singer.” Well, you can dance, I tell the Black Swan Oscar-winner. She laughs. “I don’t think that would happen. It’s a hypothetical.” What about Clinton’s decision to attend? Another coy response. “I admire her so much, and think she makes very good decisions for herself. So I respect the decisions she makes for herself.”

Portman is blunter when contrasting the president-elect with JFK: both wealthy and keen on glamour but otherwise so, so different. “Kennedy was a great proponent of civil rights and was quite revolutionary in that – and devoted his entire life to public service. Which cannot be said of Mr Trump who is, what, 50 or 60 years later in history, and is taking us backwards on civil-rights issues. And also has only just started his public-service career at 70.”

Portman is agnostic about Melania Trump: “I don’t really know anything about her, but I would hope that she would take Jackie’s example in being a proponent for a cause that she cares about, whether it’s women’s rights or immigrants’ rights, as a female immigrant herself.” (Asked later if he would consider directing another first lady biopic based on Melania Trump, Larraín shuddered: “No, no, no, no. I need to feel love for the characters that I work with.”)

In contrast to those fleeing to Canada, Portman says Trump’s victory roots her deeper in the US. “I feel very excited to be part of the voices that are going to be speaking out against injustice. It’s a time when I wouldn’t want to live anywhere else because it would be hard if you’re living far away from your own country that you care about and want to help make things better. Not being able to be really close would be hard. I’d rather be here and …”

Lead the resistance? A half-joke. She is, after all, Princess Leia and Luke Skywalker’s mum. Portman smiles slightly and continues. “And be part of making things better, and trying to help my own community.”

Portman, born in Jerusalem to an American mother and Israeli father, is Jewish. She told an interviewer she would like to have French citizenship. But last year her husband, the dancer and choreographer Benjamin Millepied (they met on Black Swan), abruptly quit his job as dance director of the Paris Opera Ballet, citing racism among other things. Does Portman share the perception, common in the US, of surging antisemitism in France?

“It seems hatred and racism in general is on the rise – or maybe being brought into the light more than previously. People are certainly feeling that they’ve been given licence to speak openly about it.” She says she witnessed a few incidents in Paris. “Not extreme but there were moments. I heard kids pushing each other, calling each other ‘Jew’ as an insult. But, you know, that was once in two years. It wasn’t a widespread phenomenon that I experienced.” She shrugs off the reported desire for French citizenship. “I don’t have any plans [to apply].”

There is a poised self-possession to Portman, an ability to play the fame game but retain distance and privacy. Not for nothing has Tom Hanks referred to her “unknowable mystery”. Yet she has been a movie star since the age of 11, when she starred opposite Jean Reno’s hitman in Léon. As a teenager, she played galactic royalty in Star Wars, paused her career to study psychology at Harvard (“I don’t care if [college] ruins my career, I’d rather be smart than a movie star,” she said), returned to the big screen in Garden State, Closer, V for Vendetta and The Other Boleyn Girl before her Oscar turn, as a ballerina who is cracking up, in Black Swan.

Portman accepting her Oscar for Black Swan. Photograph: Jason Merritt/Getty Images

A directorial debut with A Tale of Love and Darkness (2013), based on Amos Oz’s autobiographical novel, received respectful reviews. She has starred in some recent duds – Knight of Cups, Jane’s Got a Gun – but remains in the enviable position of toggling between lucrative blockbusters, such as Thor, and critically acclaimed fare with statuette-potential.

She has worked with A-list directors – Luc Besson, Mike Nichols, Wes Anderson, Darren Aronofsky, Terrence Malick – but cites Larraín, a Chilean, who may win Oscar nominations for both Jackie and the Pablo Neruda biopic Neruda (the latter in the foreign-language category), as perhaps the pick of the bunch. “Pablo is one of the best, if not the best, director that I’ve ever worked with. He has an incredibly original point of view. He sees things like nobody else. The directions he gives are things I would never think of myself. He knows how to create tension in every scene, and find humour in the darkness, or vice versa.”

Cinema has a fetish for putting idealised women through the wringer, and in the process reducing them to victim or kick-ass hero, but Larraín and Oppenheim allowed her Jackie Kennedy to be multiple, contradictory things, says Portman. “She can be brave, and self-interested, and vulnerable, and super-tough, and sensual, and cold, and all of these things at once because that’s how human beings are. A lot of films that try for a ‘feminist’ portrayal will just make a woman be really tough. Well, that’s not feminist because it’s not allowing the woman to be a human being. No one’s just tough.”

For Jackie, Portman dug out psychology texts and read up on self, identity and memory. “It was so complicated for her to have such a public identity. But of course [it was] one that she put out. And one that was manipulated by others.” Memory can further splinter a sense of self, she says. For instance, Jackie Kennedy apparently could not remember scrambling on to the back of the car immediately after the shooting. “But there are images of that, so it happened. How terrifying it is to be in a state where you’re doing something but can’t remember it and the whole world knows it exists … [yet] how quickly she overcame it. This survival instinct came in.”

Portman bristles when people say the world would be better if run by women. “No. We’re human beings. There are good ones, there are bad ones, and everyone is going to be a mix of everything. We should know by now that female leaders aren’t inherently better people or inherently better anything. I don’t think there are gender differences in the quality of work of anything – as artists, as business people, as human beings. It’s simply humans. And women have been excluded from many opportunities.”

Hollywood, she says, is a major offender. “Every year it’s exclusively male-directed, written and filmed movies that we’re talking about in awards season. Not that men shouldn’t be making films,” she smiles. “I love watching men’s films. It’s just crazy that there is such a minority of women’s voices out there.” Everyone has a responsibility to promote inclusion, she says. “If someone notices that there’s only one woman at the table they need to make a change. Or if they notice that there are no minorities getting prominent roles in film … they need to make a change.”

Portman says she would love to direct again, but first things first. “I will be having some maternity leave. I need to write, to take some time, get a little focus.”

With Rogue One spinning the Star Wars franchise back in time, Portman could, in theory, return as Queen Amidala, a comeback likely to cause ripples in the force given the prequels’ unloved status. She has not seen Rogue One (“Not yet; I’m dying to”) and at first sounds noncommittal about a return to the role. “No one has approached me about it at all, as far as I know.”

Would she accept an invitation? “Of course I feel very lucky to have been part of the Star Wars universe and the mythology that’s close to many people’s lives.” So she would accept? “I think they’re doing an amazing job extending the films. Sure.”

Jackie is released in the UK on 20 January.