Politics has changed forever. We no longer have a spectrum of parties from left to right, we no longer have accountable leaders, and we no longer have sustained, open debate on policy. In fact, in the sense that we have known it for a century or so, politics is dead.
In modern times politics came to focus on the process of gaining and keeping power through parliamentary representation at the national level. In the 19th and 20th centuries there was a basic transformation in the material conditions of life for the populations of industrially developed nations that enabled such a development. Thanks to an increasingly well informed and even quite literate society, by the end of the 19th century most adults were able to comprehend the bare socio-economic essentials of their lives, and they increasingly demanded a role in deciding the underlying social rules by which they lived.
In Europe this movement was often allied with the growth of trade unionism and socialism, and was clearly class-based. A left political program arose as the working classes, lower echelons of the middle classes and middle-class intellectuals arrayed themselves against the upper middle and upper classes through increasingly institutionalised political parties. In the US this straightforward class representation did not arise, mostly because of the regional politics that emerged from the Civil War and the role of religion (and even though after the 1880s the Republican Party was overtly the party of big business). In some modern nations, such as Japan, such representative class politics never arose.
Previous to this time, a rigid class system meant almost complete power lay with the upper classes who simply imposed their will on the small middle class and peasant masses through actual or threatened violence. However, industrialisation brought such basic socio-economic change that this strict hierarchy had to go.
First, the growing working classes, thrown together by industrialisation itself, organised themselves and demanded social power. Second, the more thoughtful sections of the upper middle class understood that sharing power was necessary. This was because these people were increasingly technical in their professions - bankers, industrialists, engineers, and so on - and they realised that industrial society was just too complex to run as a rigid hierarchy. Information and responsibility, therefore, had to be shared, and so, to an extent, did power. Modern, mass society simply could not function if the majority considered themselves totally disenfranchised.
However, they also noted the rise of mass media, especially cheap newspapers and magazines, which purported to inform everyone concerning the true conditions of society. Because the moneyed interests controlled most of these media forms (and afterwards the new mass media of radio, film and television), they believed such control could be used to limit the expectations of the emerging leftist political parties. In essence, their grand strategy was to control democratic politics by controlling information flows.
Nonetheless, between roughly 1850 and 1950 the left seemed to be winning. The middle and upper classes fragmented into reactionary and progressive sections, the reactionaries wanting to turn back the clock and the progressives believing they could manage “democratic politics”.
The left seemed to be the more cohesive and the most dynamic force, further validating representative politics and mass democracy itself. Despite the grip the upper classes maintained on high finance, the mass media and many basic institutions of the state and commerce, leftist political parties regularly won office. At such times they put forward programs of social reform, generating the welfare state. Because they focused on society more broadly, the left did best in times of crisis, such as after the two world wars and in the great depression, when people felt most insecure.
This political transformation, and especially the relative democratisation of politics, was brought about by a radical change in the basic techno-economic conditions.
Initial industrialisation, when entirely new forms of energy, materials and machines were invented and developed, gave way to a phase of mass-industrialisation which changed the whole world. An age of massive formations - technological, commercial, military, and also political - was at hand.
This phase of global development peaked with the global wars from 1914 to 1945 and the immediate aftermath. By the late 1960s things were changing and a new phase based in new technologies (computers, jet airliners, satellites) and heightened global competition (which saw the rise of new economic powers like Japan and the Asian Tigers) occurred, along with the decline of safe, unionised jobs in the developed countries.
All these things weakened the two main pillars of leftist politics - organised labour and activist national governments.