War in Ukraine and the threat of conflict in the Baltics raise fundamental questions about the West’s military alliance. What is NATO for? And is it up to the job? More countries have been joining the club, but those who foot the bill seem to be becoming less keen to do so. Do would-be aggressors still believe that an attack on one NATO member would be treated as an attack on all? Our witnesses include a former senior commander and the man who, until a few months ago, led the alliance.

(Photo: Romanian army soldiers from the guard regiment hold NATO membership countries' flags at NATO flag raising ceremony in Bucharest, 2004. Credit: Daniel Mihailescu/AFP/Getty Images)

79-year-old King Salman has taken the Saudi throne, promising security and stability. But what do his past and his first acts as king tell us about how the country might change under his rule and beyond? Our Inquiry hears from a newspaper editor and an ex-spy who have both met him and from Saudis who hope for change.

Presenter: Helena Merriman

Photo: New Saudi King Salman attends a ceremony following the death of the late Saudi King at the Diwan royal palace in Riyadh (Credit: Reuters)

Most of the nearly 300 girls kidnapped from a school in northern Nigeria last year are still missing. Their plight temporarily brought global focus to a hideous insurgency that seems to produce new horrors every day.

More than 17,000 people have died and a million have been displaced in the Nigerian army’s six-year fight with Boko Haram. The army has been rocked by mutinies – including in the division created to fight the militants - and soldiers in other parts of the country have been dismissed for refusing orders to fight in the north. Meanwhile, human rights groups say the army can be nearly as brutal to civilians as the militants are. And in a sign of apparent growing impatience, Nigeria's neighbours have begun sending their own armies against Boko Haram. So this week we ask, Is the Nigerian Army Failing?

(Photo: Some of the 59 Nigerian soldiers facing trial on charges of mutiny and conspiracy to commit mutiny over claims that they refused to fight Boko Haram militants sit handcuffed on October 15, 2014 in the military courtroom in Abuja. The soldiers, all members of the 111th Special Forces Battalion, all pleaded not guilty in court. They are also accused of refusing to deploy in August to recapture the towns of Yelwa, Bellabulini and Dambo in Borno state from Boko Haram, according to the charge sheet. Credit: AFP/Getty Images)

After the recent high-profile spat with the US over The Interview – a Hollywood film that mocks North Korea’s enigmatic leader – what do we know about his ambitions? Our expert witnesses include the first Western journalist to open an office in Pyongyang, a businessman who trains North Koreans and an admirer of Kim Jong Un who says he will succeed where his father and grandfather failed.

(Photo: Kim Jong Un. Credit: Associated Press)

The murder of more than 130 students at an Army school in Pakistan last month shocked the world. In the following days, Prime Minister Nawaz Sharif promised a comprehensive campaign to defeat the Taliban. More than 50,000 Pakistanis have died in militant attacks since 9/11. Pakistani presidents and prime ministers have previously vowed to crack down on militants. But the United States and others have said Pakistan has long harboured "snakes in the back yard" – militants who sometimes benefit the state's interests. Prime Minister Sharif says no longer will there be a distinction between "good" and "bad" Taliban. "We have resolved to continue the war against terrorism till the last terrorist is eliminated," he said. Is he right? Will this time be different? As we'll hear, the stakes extend beyond Pakistan's borders. Experts include a man who has negotiated with the Taliban, a historian on the rise of militancy and a retired Pakistani Army brigadier general.

(Image: Pakistan's Prime Minister Nawaz Sharif. Credit: Reuters)

Billions of dollars are pouring into the latest investor craze - artificial intelligence. But serious scientists like Stephen Hawking have warned that full AI could spell the end of the human race. How seriously should we take the warnings that ever-smarter computers could turn on us? Our expert witnesses explain the threat, the opportunities and how we might avoid being turned into paperclips.

(Photo: An artificial intelligence concept illustration. Credit: Shutterstock)

On 8 December at a summit in London Britain’s prime minister David Cameron told delegates from 50 countries and 26 tech firms that online child exploitation “existed on an almost industrial scale" around the world. He announced an “unprecedented package of global action” to hunt paedophiles who use the internet.

And just weeks before that a committee of British politicians revealed their belief that the intelligence services could have stopped a May 2013 terror attack in London if Facebook had alerted the authorities to an online exchange between one of the attackers and another extremist.

In this edition of The Inquiry we ask: Can the internet be policed?

Presenter: Jo Fidgen

(Photo: Big Data. Credit: Carlos Amarillo)

In November President Obama stepped onto a plush red carpet at the end of a White House corridor. “My fellow Americans,” he said, “tonight I want to talk to you about immigration.” He promised to bring change through executive action. “And to those members of Congress who question my authority to make our immigration system work better,” he said, “or question the wisdom of me acting where Congress has failed, I have one answer - pass a bill.”

That was a dig at his Republican opponents who control the House of Representatives. They failed to pass a bill last year to reform immigration. But that night, after Mr Obama finished speaking, the Republican leader in the House had his own harsh words for the president: “That’s just not how our democracy works,” he said, “the president has said before that he’s not king. And he’s not an emperor. But he’s sure acting like one."

With Republicans now in control of both the House and the Senate, the risk of continued political paralysis in Washington is very real. Many Americans are angry; turnout at the recent mid-term elections hit a 72-year low. Is American democracy broken?

(Photo: American Flag. BBC copyright)

In the last six months the price of oil has collapsed dramatically. It has been called an oil shock. Previous oil shocks have had profound and long-lasting effects. No single commodity is more important to the global economy – and therefore to global politics. What are the political consequences of cheap oil? Contributors include an ex-president of Shell Oil, a former US energy secretary and one of the world’s leading thinkers on the subject.

(Image: Oil rig in the North Sea. Credit: Press Association)

Swedish politics has for decades been the very model of stability. Not any longer. Earlier this month a far-right party which holds the balance of power in Sweden’s parliament sided with the opposition to defeat the government. A snap election has been called, just months after the government was formed.

In Greece, where EU-imposed austerity has fuelled extreme politics, the radical left Syriza party could soon have a shot at gaining power. It is already the main opposition.

Elsewhere in Europe – in France, Spain, Hungary, Italy and elsewhere – far right and hard left parties have gained popular support and parliamentary seats, threatening the political centre. Can Europe resist the rise of radical politics?

(Photo: Shadow of Marine Le Pen. Credit: Jeff Pachoud/AFP/Getty Images)