“Bring back our girls.” That is the slogan that has swept the world, following the kidnapping of more than 250 schoolchildren in Nigeria by the terrorist group Boko Haram. And on Monday, the cries redoubled in strength, after half of the children were paraded on video by the group’s leader, Abu Bakar Shekau, who claimed he had “liberated” them by converting them to Islam and demanded the release of the captured members of his group. But I have a question. If Boko Haram do not bring back our girls, what are we going to do about it?

I only ask because last week, Michelle Obama, the wife of the most powerful man on the planet, did a strange thing. She sat in the White House and held up a sign, saying: ‘Bring back our girls’. She then proceeded to deliver a radio address — unprecedented for a First Lady — in which she said: “In these girls, Barack [Obama] and I see our own daughters.” She was not alone: Last Sunday, during a break in his interview with the BBC’s Andrew Marr, British Prime Minister David Cameron stood next to CNN’s chief international correspondent, Christiane Amanpour, and held up an identical piece of paper. ‘Bring back our girls’, Her Majesty’s First Minister demanded.

On one level, the reaction to the abduction has been uplifting. It has been spontaneous. It has gone global. It has been driven by ordinary people and taken up by their elected representatives. The world has said: “We will not let this stand.” Or has it? Dozens of children have been snatched from their families. And save for getting some very prominent people to wave hand-written signs, what have we actually done? What do we want to be done?

Presumably, one of the things we want is for Boko Haram to do what they are being asked to do, which is to bring the girls back. Fine. But precisely when did we start negotiating with terrorists for the release of kidnapped victims? When did we start doing it in public? And who decided to commission the British prime minister and the US first lady to act as informal hostage negotiators? Boko Haram has secured the attention of the world. It has secured the personal attention of Obama’s wife. What lesson is it likely to draw from that? And what lesson will other terrorist organisations draw from it? Of course, it may be that the current campaign is directed as much at the Nigerian government as at the kidnappers themselves. But Nigeria is a sovereign state. And I thought the conventional wisdom was that when western powers such as Britain and the US throw their diplomatic weight around, it’s counterproductive. Smacks too much of the old imperialism — especially in Africa. That is certainly the rationale deployed whenever anyone recommends doing something about Robert Mugabe: Any attempt to remove his subjects from his clutches, during his regime’s darkest days, was met with accusations of colonialism.

However, let us accept that we have decided, collectively, that “something must be done”. But what happens if nothing is? We could put up more signs. Bigger signs. Get more high-profile advocates. Hold a fund-raiser — a pop concert, perhaps. Get Bring back our girls to Number One. Or perhaps we should actually go and get them. Britain and America could send some big, rough men, with very big guns, to say to Boko Haram: “We’ve come to take our girls back. And if you try to stop us, it’ll be the last thing you ever do.” Personally, I’m all in favour. And I suspect that, if the world woke up tomorrow to discover we had done precisely that, the world would cheer. The old concerns about foreign adventurism, about putting “our boys” in harm’s way, would be set aside if “our girls” were reunited with their families. But then what happens next week, when Boko Haram snatches some more girls? Or if they are not snatched from a village in Nigeria, but a village in Syria? Or Afghanistan? Or if groups of masked thugs start snatching schoolgirls in Ukraine?

I understand the flaws in the argument that “because we can’t do everything, we shouldn’t do anything”. I just want to know what the rules are. Boko Haram, for example, has been active for a decade. It was formally classified as a terrorist organisation in 2013. It has been responsible for 10,000 deaths. And to date, no one has seriously argued that we should lift a finger against it. Do we want to be the world’s policemen or do we not? If we don’t, then fine. But let us take down the signs, and the Twitter hashtags, because all we are doing is communicating our own impotence. Equally, if the West does want to be the world’s policemen, then it has to do the job properly. It cannot say to a Nigerian mother and father: “Your girl is our girl”, and then say: “Sorry, that was last week. Your girl isn’t our girl any more.”

Nor should the West say it to a Syrian mother and father, or an Afghan mother and father, or a Ukrainian mother and father. But that is precisely what the West is preparing to say. Asked in December about their plans for the education of girls after the West’s withdrawal from Afghanistan, and their possible seizure of power, a spokesman for the Taliban reassured his interviewer that their rights would be protected. He then added: “All forms of education will be subject to the Islamic Emirate, from the curriculum and teachers, to the schools and equipment. The enemy is misconstruing what they call ‘women’s issues,’ or ‘girls’ education,’ or ‘human rights’, but they will not fool anyone in Afghanistan.” No one appears to have told the Taliban that these children are our girls. In Syria, meanwhile, they’re not kidnapping schoolgirls: They are gassing them to death.

Last week, a 16-year-old named Maryuma became the latest victim of one of Bashar Al Assad’s chlorine attacks. She breathed in the gas, which then formed into hydrochloric acid and burnt away her lungs. Unfortunately for Maryuma, it turned out that she lived on the wrong side of one of those famous “red lines” that used to be so important to us. Let us for one horrific moment speculate about what would have happened if those pupils in Nigeria had not been taken from their school. What if they had been murdered in their school? Would they still have been our girls? The answer is no. On February 25 of this year, Boko Haram attacked a boarding school in a town called Buni Yadi, killing 59 children. Most were shot. Some had their throats cut. Several more were locked in a classroom and burnt alive. That day, Michelle Obama tweeted a picture of herself working out with a presenter from the US version of The X Factor.

Over the weekend, I watched some of the Eurovision Song Contest. Whenever Russia got a point, they were booed. And I realised: This is the new progressive interventionism. We will let them annex your country. But once they have finished invading, we will boo their Eurovision entry. Some people may see this as an improvement: There was a time when the West would have sent a gunboat. Now, it sends an angry tweet. Far more civilised. But if that really was my daughter in the clutches of Boko Haram, I would want people to do more than tweet. I would want my prime minister to do more than just hold up a hand-written sign. And I would want the wife of the most powerful man on earth to convince her husband to deploy more than a radio broadcast to save her.

— The Telegraph Group Limited, London, 2014