It's impossible to reduce entire eras down to one paritcular phenomena. But it's not too broad a generalisation to say that the workers movement between 1889 and 1914 was a period of slow accumulation of strength, of small battles, of election campaigns, of the spread of (albeit often bastardised) socialist ideas. 1914-1923 was a period of movement, of mass strikes, insurrections and the building of radical, new forms of democracy.
Despite the collapse of the Second International over the war, the years of slow accumulation were not entirely in vain. The heroes of the revolutionary period all came from the Second International. The Bolsheviks were a faction in a Second International party. The heroes of the revolution however, either through neccessity or foresight, had split from the rest of the international.
As the as the class war cooled across Europe there began a ruling class offensive. The disunity of the workers movement was a deadly liability, as proven in Italy in 1922. The tactic of the united front, providing practical unity while maintaining politcal/organisational differences was the neccessary response.
The one of the interesting twists of our period is that we are having to do (in our own ways) the job of the second and third internationals. Working class consciousness is always varied, in the west it is generally lower than it was thirty years or so ago. It needs to be raised. However, the working class is moving, even if, like in Britain for example, the people involved don't recognise themselves as the working class in motion, as is the case with the anti-war movement.
There have been two responses to this question, one is the broad party, the other is the political coalition or bloc. The broad party seems to be a decent, non-sectarian answer, until that is it comes into contact with the movement. In any broad party there are tendencies.
When it comes to politically expressing itself the broad party either takes the line of the majority or dominant tendency, or it falls into confusion, members take whatever line they choose; then you no longer have a party but an autonomist network.
Either way you do not get a satisfactory response to the demands of a movement. Take the socialist newspaper, a traditional tool of the left. It can either be a means of building a network around activists, providing a coherent intervention into a movement, or it can be a battleground for different tendencies: outwardlooking or inwardlooking.
The political coalition, I would argue, allows scope for disparate groups, some of whom may not regard themselves as 'socialist' or traditional working class, to agree on common goals and attempt to achieve them via their various ways and means. There can be unity in action and and honest comparison between each group's politics and organisation.