It would have been easy enough to imagine the 25th anniversary of the Eastern European revolutions being marked with a conference on liberty held in honour of Lady Thatcher — a conference which was held this week. But that is just about the only thing which could possibly have been foreseen from the vantage point of a quarter of a century ago. Who could have predicted then that the stream of Eastern European migrants flooding westwards in the hope of a better life, so welcomed then in their Trabants, would come to be seen so negatively that the desire to keep them out caused the rise of a fourth party in British politics?

Even harder to foresee from the month of Tiananmen Square was the economic rise of China. In 1989 the rules of politics and economics seemed simple: freedom equalled economic success and dictatorship stagnation. No one imagined that a still-communist China — albeit a less malign one than 25 years ago — could so quickly become the world’s second largest economy, while a post-communist Russia would remain in the doldrums, a hotbed of corruption.

But hardest of all to foresee was the domination in world affairs of fundamentalist Islam. By 1989, admittedly, the Iranian revolution was a decade old. The day of Tiananmen Square also saw the death of Ayatollah Khomeini, the leader of that revolution. It seemed probable then that his passing would mark the beginning of the end of this reversion to theocracy, which ran so against the triumph of liberal democracy in the West: a triumph which seemed so absolute that, soon after the fall of the Berlin Wall, a political scientist at Harvard, Francis Fukuyama, was inspired to write that we had arrived at the end of history.

That now seems like the unfulfilled promise of an England World Cup performance. Instead, the world is pulling strongly apart in two directions: towards liberalism in the West and towards religious absolutism — complicated by it coming in numerous brands — in the Middle East. Then there is the dash for influence in Africa, in which China has its nose ahead, and the revival of socialism in parts of South America. And, of course, there is the attempted reconstruction by Putin of the Russian empire: not this time in communist format but no less dangerous for that.

For foreign policy-makers all this must make the certainties of the Cold War seem attractive. At least then, apart from the odd act of terror from General Gaddafi, there was only one real enemy, and that a weakening one from the 1970s on. Moreover, rivalry between the West and the Soviet Union was a game that had clear rules. We arrested spies, while pretending not to spy ourselves. We rattled our missiles, with confidence that we would never use them. Skirmishes were limited to the conference chamber. Above all, we were certain of the values we wished the rest of the world to adopt: economic and personal freedom.

We still stand for these values, of course, but our commitment has weakened. Too many fruitless military adventures have demonstrated the pointlessness of trying to introduce democracy to parts of the world where it is still regarded as an alien concept. We cannot even guarantee its survival in Europe. In the 1980s we still had a military that was capable of defending us and, with co-operation, our western European neighbourhood. Since then, the neighbourhood has grown, but our will and ability to defend it has not. Where are the lines beyond which Putin knows he must not tread? There are none.

The end of the Cold War, ministers used to think, would bring a peace dividend. The military could be safely cut and the money spent instead on social programmes. How foolish that seems now. While government of both colours trimmed the forces, fighting real wars — as opposed to a cold war — came back into fashion. The first Gulf War deluded us into thinking that they could be fought from 30,000 feet with next to no loss of western lives. After that, as we tried to fight more with less, the wars steadily became messier, culminating in the quagmire of Iraq and Afghanistan. They leave behind them something else which would have been unimaginable in 1989: that it would be a former Labour Prime Minister who ended up being ridiculed as a vainglorious warmonger.

Tony Blair’s insistence that the rise of yet another Islamic group waging holy war in Iraq has nothing to do with his and George Bush’s invasion of that country 11 years ago deserves the ridicule to which it has been subjected. But Blair at least had a vision, even if he and Bush had poor plans. The same cannot be said of Cameron and Hague. Do we still stand for enlightened intervention or do we not? And if we do, why not in Syria? British foreign policy has been badly exposed by the collapse of US foreign policy, which in recent times our own has so blithely followed. In his speech to West Point graduates last month, President Obama spoke of a US policy of ‘might doing right’. But to judge from his actions, he believes the US doing right is the US doing next to nothing beyond its own borders.

Donald Rumsfeld was much mocked for saying that weakness is more provocative than strength. But there’s a lot of truth to his words. In a quarter of a century we have gone from Cold War to enlightened intervention to one of doing nothing but mopping up the refugees from failed states. It is an inglorious role for western powers who briefly seemed so triumphant in that summer 25 years ago.