BERLIN — The German capital on a sunny Sunday afternoon is about as laid-back a place as may be imagined. Couples lounge in the grass beside the Landwehr Canal in the Tiergarten, jugglers perform, kids on bikes in bright helmets zigzag through the throng.

The city, it seems, has not a care in the world.

Just back from the water there is a small memorial to Rosa Luxemburg, the socialist revolutionary murdered in 1919 by rightist paramilitaries. Her body was tossed in the canal. The murder presaged two decades in which Germany would be the crucible of a fierce struggle between left and right, Marxism and Fascism.

Across Europe, opposing ideas vied for the minds of the masses tugged into cities by industrialization, radicalized by the devastation of war, polarized by the Bolshevik revolution in Moscow. Politics was the battleground of capital and labor, industry and the proletariat. Rightist revanchists confronted Marxists bent on wresting control of the means of production. The Weimar Republic, aptly described by the novelist Alfred Doblin as a political set-up lacking “proper instructions for use,” was never free of political violence. Out of it, in 1933, came Hitler and his marauding SA Brownshirts. It did not take them long to trash every independent institution and turn Germany into a lawless dictatorship.

The Nazis’ first business was with the left — socialists and communists who, unlike Luxemburg, had survived. The first concentration camps, like Dachau, were filled with them. The battle of ideas had to be settled, the left extinguished. The Jewish question could be resolved later, even if Jewish leftists (or “Judeo-Bolsheviks” as the Nazis called them) were immediately the object of particular vitriol and violence, the fodder on which the SS prepared for the greater savagery to come.

All this was not so many decades ago. Yet sometimes you have to pinch yourself to be reminded that politics was the business of the 20th century and Berlin the epicenter of an ideological struggle that involved two world wars and the prolonged division of Europe. What, you may ask, is Rosa Luxemburg to Sunday lovers? And what does politics amount to today?Most Westerners today are no longer driven by politics. By that I mean that they are no longer possessed by political ideas that they feel can change society. There is no great clash of ideologies. Politics in the 21st century has largely lost its capacity to inspire, or if there is a gust of inspiration (as with early Barack Obama) it proves illusory.

People are focused on other matters: personal health, spiritual health, wellness, diet, living longer, and the vast related matter of the health of the planet. Zen, yoga and the soul have trumped the means of production. Of course, wellness in turn raises the issues of climate change and energy consumption, questions that have considerable political content but are not political at their core. The political century has given way to the personal century.

That is one reason why the 20th century already seems so distant, why the Berlin of then and the Berlin of now appear almost unrelated and stumbling on a memorial in the Tiergarten so strange. The last century’s great battles no longer resonate. They bear little relation to people’s harried lives. They are almost quaint.

Technology has built links everywhere, binding humanity as never before, but it has also fragmented people into the solipsistic, magnetic world of their hand-held devices. These devices can be political tools that gather protest movements from Rio to Istanbul, but the movements tend to prove weak because leaderless. The devices are also numbing, isolating and depoliticizing in their idolization of self.

There are, of course, political stirrings in Europe. The political center, and the area just to the left and just to the right of it, seem dead, one reason for the rise of leftist parties like Syriza in Greece, rightist parties like the National Front in France, anti-immigrant nationalists from Sweden to the Netherlands, and big protest movements against the political establishment (of any stripe) like Podemos in Spain. At the heart of all this, it seems, is a sense that something fundamental is amiss in the economies of Western societies.

I said the personal has trumped politics in the 21st century. But of course the link between personal wellness and planetary health is not just about climate change or clean energy. It is also about how the planet’s limited resources are divided up. That division is heavily, and increasingly, skewed toward the very rich. When too much is concentrated in too few hands, a reaction begins. The success of Podemos, or in a small way of the left-wing message of Bernie Sanders in Iowa, is a reflection of this.

Politics is not dead, but it’s dormant, and Berlin remains a useful reminder of how virulent political ideology can be in a climate of social unrest.