A historian (I think it's A. J. P. Taylor, but can't quite remember) relates the following anecdote. Two Russian exiles are arguing in a Vienna park about the coming Russian Revolution sometime before WWI. The more cynical of the pair asks the other: "And exactly who is going to lead this revolution, Bronstein in the cafe over there?" Bronstein was of course Trotsky.
Touring the US a few years ago, the Guardian columnist George Monbiot compared Tea Party meetings to leftwing ones. He said that the TP mobilized people to do things, while speakers at left meetings simply offered their ideas and opinions in hopes that people in the audience might agree. This is also an important difference between Lenin and Trotsky, on the one hand, and leftist intellectuals of today. The former two were writers, but writing books and articles was only one (very important) facet of their political activity. They were above all revolutionary politicians. Much of their writing aimed to persuade fellow members of the socialist movement to a particular course of action, or, in works of a more theoretical nature, to establish a general orientation toward political practice.
Today's leftwing intellectuals, on the other hand, have no organizational attachments (except perhaps to the universities they teach in or the journals they write for). They simply offer up their opinions and ideas to the public at large. They don't lead anyone; they are simply individuals with opinions. I'm not denigrating their activity. Their analyses may help people to understad things better, or shape their attitudes. But what they write or say has no direct consequences. What Lenin and Trotsky wrote and said often did because they were not freelance intellectuals, but part of an organized movement.
Jim Creegan