The Final Year: The breathless story of Obama’s last days as president

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Power is a central character in Greg Barker’s film, and one of the most compelling. In one scene she cries as she tells new immigrants about the time in her life when she, at the age of nine, emigrated with her mother from Ireland, leaving behind her alcoholic father.

For Power, America really has been a land of opportunity. She went from high school in Atlanta to Ivy League Yale. A summer internship at CBS led to assignments covering the wars in Bosnia and Darfur. At Harvard Law School she drew on those experiences to write A Problem from Hell, a book condemning America’s indifference to such atrocities, which won her a Pulitzer Prize and caught the attention of a young senator named Barack Obama.

He called her. They had dinner. Beguiled, she left her job as a Harvard professor to work for him, and three years later became a senior adviser in his 2008 presidential campaign. The high point of that year was meeting Cass Sunstein, a Harvard legal scholar who was also advising Obama: they married in Ireland’s County Kerry on 4 July – Independence Day – that year. The low point was her resignation after calling Hillary Clinton, Obama’s rival for the Democratic nomination, a “monster”.

Despite that, Obama brought Power into his new administration, first as a member of his National Security Council and later – aged 42 – as America’s youngest ambassador to the UN. In that role, while simultaneously raising two young children, she was perhaps the most forceful member of a foreign policy team that was determined to restore America’s global stature.

She was seen as the administration’s “in-house conscience” and “activist in chief.” Tough but tender, she is seen in The Final Year listening to tearful Syrian refugees and comforting the mothers of Nigerian girls kidnapped by Boko Haram.

Sitting in London’s Langham hotel, Power cites successes including the Paris climate-change accord, the normalisation of relations with Cuba and the agreement to curb Iran’s nuclear ambitions. “We were part of so much that showed how US leadership could be harnessed for good,” she says.

The film ends with Trump’s victory, and scenes from Power’s desolate election-night party for 37 female ambassadors to the UN who hoped to see America elect its first woman president. Her dismay at Clinton’s defeat (they had long since made up) was compounded by what followed.

Trump has reversed America’s commitment to the Paris accord, the Iran nuclear deal and the rapprochement with Cuba. He prefers military threats and unilateralism to diplomacy and alliance-building. “The only algorithm that seems to define his foreign policy agenda is effectively asking, ‘What is the opposite of what Barack Obama did? Let me do that,’” says Power.

She finds it hard to accept the legitimacy of his election. “What’s clear is that there was a wholly illegitimate influence campaign by a foreign adversary that made a difference to many people’s votes.” She prays that by the time Trump leaves office “the damage is not so great that we will be able to recover some of what’s been lost.”

Power is now giving her two children – Declan, aged eight, and Rian, aged five – the attention they lacked while she was ambassador. “I got out in the nick of time. They are in their formative years and I am very focused on that.” She is helping friends who are seeking seats in the House of Representatives, and draws encouragement from the record number of women who have reacted to Trump’s victory by seeking elected office.

She is also writing another book, tentatively entitled The Education of an Idealist, but denies feeling chastened by the clash of her ideals with the reality of government. During her time in politics she was able to use America’s power to free political prisoners and help contain the Ebola epidemic. And she says she would return to government “in a heartbeat”.

Power hopes The Final Year (in cinemas from Friday 19 January) “will get people moving again. It’s a reminder we have to take our destiny into our own hands. What Trump’s doing renders it very important that people get inspired, and instead of just sighing or yelling at the television or at the president, they do something concrete in their community or in politics.”

As she declares at the film’s conclusion, after Trump’s triumph, “Any thought that any of us might have had that we could go gently into the night has been vanquished. We are in this for the long haul.”

The Final Year hits UK cinemas on Friday 19 January