Are we – the so-called “west” – no more than the baby Germany threw out with the bathwater? Any history of the industrialised world’s culture – scientific, technical, literary, military, philosophical, global-entertainment – has to accept the multiple creative impact of German emigration over the two previous centuries. But its best known and most spectacular source has been forced emigration, as David Blackbourn confirms. The whole world, not only America and Britain, was fertilised by the torrent of intellectual brilliance that fled Germany and Austria in the 1930s. Less well known is the earlier outflow of refugee liberals and socialists, politicians, writers or barricade fighters, after the counter-revolutions that followed the great uprisings of 1848. Most headed for the US, where many Union commanders in the civil war would be Germans who had learned their trade in Baden or the siege of Vienna. The thinkers and revolutionaries often joined London’s swarm of political émigrés.

These German currents, and especially their Jewish element, were intellectual and entrepreneurial. They taught the British, for instance, new ways to invent, design, travel, make love and stay fit. But Germany in the World recalls that “ordinary” Germans, especially peasants, had also been emigrating by the tens of thousands all through the 19th century. At first they moved into prosperous north-west Europe, including Britain (Victorian London and Liverpool were overcrowded with German waiters and clerks). But as long-distance travel grew easier, five million out of the five-and-a-half million German emigrants that century settled in the US.

As Blackbourn shows in this rich and full-throated book, the crazy paving of realms that considered themselves German was already well trodden by the rest of Europe in the 16th century. Foreign kings wanted German gunners, German miners (to extract the gold and silver of the New World), German mercenary soldiers and German investment – above all, from the Fugger banking dynasty in Augsburg. German technology powered the Reformation: “Printing was the German art and it was Germans who introduced it almost everywhere.” In the 17th century, European emperors and kings unleashed the calamity of the Thirty Years War, which fell above all on the German lands. Grass grew in the streets, cities burned and in some regions half the population perished. A narrative of German victimhood took root, adding to a baleful Lutheran narrative which taught that earthly powers (die Obrigkeit) must be obeyed even when they were satanic. In the century of Enlightenment, Germans once again served the rest of the world without much collective agency of their own. Under the Spanish flag, the Humboldt brothers explored and studied the tropical world; the naturalist Johann Forster worked in Siberia for the tsar and then, with his son Georg, sailed the Pacific with Captain Cook. German sugar planters dominated Surinam (“this small, mosquito-ridden, cosmopolitan but racially violent colony”), but it remained a Dutch possession. Old subordinate patterns prevailed. At Yorktown in 1781, the decisive American victory over the British, there were so many Hessians and Hanoverians and Ansbachers on each side that it was dubbed “the German battle”.

And yet, in the next age, the eternal lieutenant seemed at last to become a general. “Not long before his death in 1983, the French political philosopher Raymond Aron remarked that the 20th century “could have been the German century”. By 1900, a united, independent Germany had been created, which had won vast wars against Austria and then France, acquired a navy and tropical colonies, and exported its scientific, technical and intellectual triumphs across the world. Even the self-sure British crowded into German universities. Carlyle, George Eliot, Ruskin and Matthew Arnold set about learning German. “Germany in the world” seemed to be heading for “the world in Germany”.

But, of course, “it turned out differently… The German century became synonymous instead with military aggression and Nazi dictatorship, above all with the Holocaust”. Blackbourn, the professional historian, asks “When did it all start to go wrong?” rather than “Why?”. Many would answer his question with “1914”, appointing Germany as the primary culprit for the first world war. Blackbourn’s account of the “July Crisis”, which ended in war, is careful and vivid, but not identical to Christopher Clark’s contested verdict in The Sleepwalkers (2012), which stated that: “There is no smoking gun in this story; or rather, there is one in the hands of every major character.” In Blackbourn’s version, what emerges is not any deliberate German nudging towards war so much as the criminal stupidity and recklessness of German leaders handling the crisis. Their caste hated Germany’s old romantic image as a dreamy land of “thinkers and poets” (Dichter und Denker); they demanded a “place in the sun” for their “belated nation” and their paranoid sense of victimhood was confirmed after the war by the brutality of the 1919 Versailles peace settlement. The dazzling modernisms of the Weimar Republic probably excited the outside world more than the Germans. But the Nazi dictatorship that followed was, in Blackbourn’s phrase, “the party of negation”, defined by what and whom it rejected – which included influences from most of the “non-Aryan” globe. “Germany in the world” soon narrowed to mean only world war, genocide, destruction and then partition between Germany’s conquerors.

Two long concluding chapters cover Germany’s return to the world, as a West German state was steered towards independence by the US and its allies. Interestingly, Blackbourn’s account of the first postwar years lends weight to the notion that the division of occupied Germany owed more to an American decision to dig an anti-communist firebreak across central Europe than to any Soviet strategy. He gives a fair account of East Germany’s desperate efforts to compete with the other state and create a “socialist modernity”. As he says, “each [state] laid claim to be the ‘real’ or ‘better’ Germany”. Here resurfaced an old idealist daydream, born of the failure of the revolutionary Frankfurt parliament in 1848, a failure that allows malcontents in every generation to announce that “this” Germany is not yet the real thing.

In 1999, the reunited Federal Republic reluctantly took the step that, in the eyes of impatient allies, finally made “Germany in the world” a reality. German troops were sent to war in Kosovo. But it is Germany’s response to the Russian invasion of Ukraine that has shown a new international confidence – and not just by arming Ukraine with Leopard tanks. Blackbourn’s book takes readers up to Putin’s onslaught. But since then, Europe has watched Germany, led by Chancellor Scholz and his extraordinary Green minister of economy and climate, Robert Habeck, replace total dependence on Russian energy and storm ahead towards ambitious climate targets. All done in months, by a sudden mobilisation of democratic vigour. Germany, at last, gives the world a leadership that threatens nobody.

• Germany in the World: A Global History, 1500-2000 by David Blackbourn is published by Liverlight (£40). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply